SqlHelper 帮助文档及详解--项目初步搭建

微软SqlHelper类中文注释和使用方法

相关链接:  http://blog.csdn.net/itmaxin/article/details/7609566

SqlHelper.cs是N年前微软出品的一个使用ADO.Net方法对SQL Server数据库进行操作的封装类，随后有高人根据这个类写了DbHelper.cs以操作SQL Server之外的数据库，而后微软也发布了Enterprise Library企业库组件。但是对于刚开始学习ADO.Net/C#或者中小企业应用层面来说，根据SqlHelper.cs类做简单的数据库访问层的东西已经足够用了。Enterprise Library企业库虽然十分的强大，但是入手和配置都不是那么简单，杀鸡完全不用宰牛刀。

其实这个很古老的类还有一个很值得学习的地方：C#中重载的使用。每个查询数据库的方法都有8个左右的重载方法，对C#面向对象思想中的多态性不了解的，看过这些个重载方法基本上都会清清楚楚了。此外应该注意的是public sealed class SqlHelper{}：sealed修饰符修饰的类是封闭的类，是不能被继承的。

和微软发布的SqlHelper.cs不同，为了方便我把里面的SqlHelperParameterCatch.cs单独列出来了。下面的下载中还有OledbHelper.cs、OdbcHelper.cs和XMLHelper.cs可供使用，分别针对不同的数据库类型。下面略微解析一下SqlHelper.cs这个类的使用方法，其中类内部使用的私有方法不再介绍，因为公共方法的使用大同小异，所以就以最简单的ExecuteNonQuery()方法作为范例。
ASP.NET/C#语言:
下述代码是ExecuteNonQuery()的9个重载方法。
前3个算是准备查询。
[csharp] view plaincopy

    //#1-1
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText){}
    //#1-2
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText,
    params SqlParameter[] commandParameters){}
    //#1-3
    public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues){}  

中间3个是执行查询。
[csharp] view plaincopy

    //#2-1
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText){}
    //#2-2
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText,
     params SqlParameter[] commandParameters){}
    //#2-3
    public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues){}  

后面3个则是用于SQL事物查询。
[csharp] view plaincopy

    //#3-1
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText){}
    //#3-2
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText,
     params SqlParameter[] commandParameters){}
    //#3-3
    public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues){}  

再细分，

[csharp] view plaincopy

    //#2-1
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType,
     string commandText){}  

执行的是无参数的SQL语句，而

[csharp] view plaincopy

    //#2-2
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType,
    string commandText, params SqlParameter[] commandParameters){}  

执行的是包含参数数组的SQL语句（参数数组可以为空）。

[csharp] view plaincopy

    //#2-3
    public static int ExecuteNonQuery(SqlConnection connection, string spName,
    params object[] parameterValues){}  

执行的则是无返回值的存储过程。

实际上，#-1和#-

[csharp] view plaincopy

    //#1-1
    public static int ExecuteNonQuery(string connectionString, CommandType commandType,
     string commandText){}  

    //#1-3
    public static int ExecuteNonQuery(string connectionString, string spName,
     params object[] parameterValues){}  

重载是为了方便无参数的SQL语句。

而#-3和#-

[csharp] view plaincopy

    //#1-3
    public static int ExecuteNonQuery(string connectionString, string spName,
    params object[] parameterValues){}  

[csharp] view plaincopy

    //#2-3
    public static int ExecuteNonQuery(SqlConnection connection, string spName,
    params object[] parameterValues){}  

重载只是为了方便调用存储过程，他们的本质还是和#-2和#-

[csharp] view plaincopy

    //#1-2
    public static int ExecuteNonQuery(string connectionString, CommandType commandType,
     string commandText,
    params SqlParameter[] commandParameters){}  

[csharp] view plaincopy

    //#2-2
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType,
    string commandText,
     params SqlParameter[] commandParameters){}  

一样。下面是针对重载方法的一些简单使用。

. ExecuteNonQuery()执行无参数的SQL语句。
ASP.NET/C#语言:
[csharp] view plaincopy

    string sql = "INSERT INTO Customer(Country,Firstname,Lastname) VALUES('USA','Steven','Sun')";
    if (SqlHelper.ExecuteNonQuery(SqlHelper.connectionString, CommandType.Text, sql) == )
    {
        Response.Write("添加成功！");
    }  

可以简单的分析一下执行的过程：

    ExecuteNonQuery()方法根据参数不同将会首先重载#-，
    [csharp] view plaincopy
        //#1-1
        public static int ExecuteNonQuery(string connectionString, CommandType commandType,
         string commandText){}
    在#-1中设置参数数组为null，既
    [csharp] view plaincopy
        SqlHelper.ExecuteNonQuery(SqlHelper.connectionString, CommandType.Text, sql,
    [csharp] view plaincopy
         (SqlParameter[])null)。
    这时候ExecuteNonQuery()方法根据参数不同将会首先重载#-，
    [csharp] view plaincopy
        //#1-2
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText,
        params SqlParameter[] commandParameters){}
    在#-2中重载#-2方法执行查询。
    [csharp] view plaincopy
        //#2-2
        public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType,
        string commandText, params SqlParameter[] commandParameters){}
    在#-2中首先要使用私有的PrepareCommand()方法把参数放入SqlCommand中，然后执行ADO.Net的ExecuteNonQuery()方法（这个是无参数的原始方法），执行成功则返回整数1。
    剩下的就是一些判断和输出的过程了。

也可以自己写一些别的方法验证其他重载方法的时候，在Visual Studio中按F11可以逐语句的查看执行的过程，下面两个方法的使用也是一样的，所以就只贴代码了。
. ExecuteNonQuery()执行有参数数组的SQL语句。
ASP.NET/C#语言:
[csharp] view plaincopy

    //修改指定CustomerId的顾客的国籍
    string sql = "UPDATE Customer SET Country=@Country WHERE CustomerId=@CustomerId";
    SqlParameter[] param = new SqlParameter[]
    {
        new SqlParameter("@Version", SqlDbType.VarChar),
        new SqlParameter("@CustomerId", SqlDbType.Int)
    };
    param[].Value = "England";
    param[].Value = ;
    if (SqlHelper.ExecuteNonQuery(SqlHelper.connectionString, CommandType.Text, sql, param) == )
    {
        Response.Write("修改成功！");
    }  

. ExecuteNonQuery()执行无返回值的存储过程。
SQL Server语言:
[sql] view plaincopy

    CREATE PROCEDURE [dbo].[SP_ExecuteNonQuery]
    AS
    BEGIN
    INSERT INTO Customer VALUES('Japan','Beautiful','Girl')
    END  

ASP.NET/C#语言：
[csharp] view plaincopy

    if (SqlHelper.ExecuteNonQuery(SqlHelper.connectionString, "SP_ExecuteNonQuery") == )
    {
         Response.Write("执行无参数存储过程成功");
    }  

其他方法都是类似的，这个类中我们常用的方法如下：

    ExecuteNonQuery(): 执行简单的无返回值的查询。
    ExecuteDataset(): 返回Dataset的查询，相当于返回一个数组。
    ExecuteReader(): 使用DataReader读取数据。（注：少量数据的情况下使用SqlDataReader的效率高于使用Dataset）
    ExecuteScalar(): 返回结果集中的第一行第一列，相当于返回单个值。

其他的方法使用的较少，就不介绍了。强烈建议使用Visual Studio 2010调试这些程序，下面是这几个类的下载地址，如有问题，欢迎和我一起探讨。

在原文的基础上稍有改动。

参考自：“一个人飞”博客。

SqlServer数据访问帮助类---SqlHelper(带详细中文注释)

using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;

namespace hkszyy
{
 /// <summary>
 /// SqlServer数据访问帮助类
 /// </summary>
 public sealed class SqlHelper
 {
  #region 私有构造函数和方法

  private SqlHelper() {}

  /// <summary>
  /// 将SqlParameter参数数组(参数值)分配给SqlCommand命令.
  /// 这个方法将给任何一个参数分配DBNull.Value;
  /// 该操作将阻止默认值的使用.
  /// </summary>
  /// <param name="command">命令名</param>
  /// <param name="commandParameters">SqlParameters数组</param>
  private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
  {
   if( command == null ) throw new ArgumentNullException( "command" );
   if( commandParameters != null )
   {
    foreach (SqlParameter p in commandParameters)
    {
     if( p != null )
     {
      // 检查未分配值的输出参数,将其分配以DBNull.Value.
      if ( ( p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input ) &&
       (p.Value == null))
      {
       p.Value = DBNull.Value;
      }
      command.Parameters.Add(p);
     }
    }
   }
  }

  /// <summary>
  /// 将DataRow类型的列值分配到SqlParameter参数数组.
  /// </summary>
  /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
  /// <param name="dataRow">将要分配给存储过程参数的DataRow</param>
  private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
  {
   if ((commandParameters == null) || (dataRow == null))
   {
    return;
   }

   int i = ;
   // 设置参数值
   foreach(SqlParameter commandParameter in commandParameters)
   {
    // 创建参数名称,如果不存在,只抛出一个异常.
    if( commandParameter.ParameterName == null ||
     commandParameter.ParameterName.Length <=  )
     throw new Exception(
      string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName ) );
    // 从dataRow的表中获取为参数数组中数组名称的列的索引.
    // 如果存在和参数名称相同的列,则将列值赋给当前名称的参数.
    if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring()) != -)
     commandParameter.Value = dataRow[commandParameter.ParameterName.Substring()];
    i++;
   }
  }

  /// <summary>
  /// 将一个对象数组分配给SqlParameter参数数组.
  /// </summary>
  /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
  /// <param name="parameterValues">将要分配给存储过程参数的对象数组</param>
  private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
  {
   if ((commandParameters == null) || (parameterValues == null))
   {
    return;
   }

   // 确保对象数组个数与参数个数匹配,如果不匹配,抛出一个异常.
   if (commandParameters.Length != parameterValues.Length)
   {
    throw new ArgumentException("参数值个数与参数不匹配.");
   }

   // 给参数赋值
   for (int i = , j = commandParameters.Length; i < j; i++)
   {
    // If the current array value derives from IDbDataParameter, then assign its Value property
    if (parameterValues[i] is IDbDataParameter)
    {
     IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
     if( paramInstance.Value == null )
     {
      commandParameters[i].Value = DBNull.Value;
     }
     else
     {
      commandParameters[i].Value = paramInstance.Value;
     }
    }
    else if (parameterValues[i] == null)
    {
     commandParameters[i].Value = DBNull.Value;
    }
    else
    {
     commandParameters[i].Value = parameterValues[i];
    }
   }
  }

  /// <summary>
  /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数
  /// </summary>
  /// <param name="command">要处理的SqlCommand</param>
  /// <param name="connection">数据库连接</param>
  /// <param name="transaction">一个有效的事务或者是null值</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
  /// <param name="commandText">存储过程名或都T-SQL命令文本</param>
  /// <param name="commandParameters">和命令相关联的SqlParameter参数数组,如果没有参数为'null'</param>
  /// <param name="mustCloseConnection"><c>true</c> 如果连接是打开的,则为true,其它情况下为false.</param>
  private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection )
  {
   if( command == null ) throw new ArgumentNullException( "command" );
   if( commandText == null || commandText.Length ==  ) throw new ArgumentNullException( "commandText" );

   // If the provided connection is not open, we will open it
   if (connection.State != ConnectionState.Open)
   {
    mustCloseConnection = true;
    connection.Open();
   }
   else
   {
    mustCloseConnection = false;
   }

   // 给命令分配一个数据库连接.
   command.Connection = connection;

   // 设置命令文本(存储过程名或SQL语句)
   command.CommandText = commandText;

   // 分配事务
   if (transaction != null)
   {
    if( transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
    command.Transaction = transaction;
   }

   // 设置命令类型.
   command.CommandType = commandType;

   // 分配命令参数
   if (commandParameters != null)
   {
    AttachParameters(command, commandParameters);
   }
   return;
  }

  #endregion 私有构造函数和方法结束

  #region ExecuteNonQuery命令

  /// <summary>
  /// 执行指定连接字符串,类型的SqlCommand.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
  /// <param name="commandText">存储过程名称或SQL语句</param>
  /// <returns>返回命令影响的行数</returns>
  public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
  {
   return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定连接字符串,类型的SqlCommand.如果没有提供参数,不返回结果.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
  /// <param name="commandText">存储过程名称或SQL语句</param>
  /// <param name="commandParameters">SqlParameter参数数组</param>
  /// <returns>返回命令影响的行数</returns>
  public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );

   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
   }
  }

  /// <summary>
  /// 执行指定连接字符串的存储过程,将对象数组的值赋给存储过程参数,
  /// 此方法需要在参数缓存方法中探索参数并生成参数.
  /// </summary>
  /// <remarks>
  /// 这个方法没有提供访问输出参数和返回值.
  /// 示例:
  ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串/param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配到存储过程输入参数的对象数组</param>
  /// <returns>返回受影响的行数</returns>
  public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果存在参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组.
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数情况下
    return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
  {
   return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
  /// <param name="commandText">T存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamter参数数组</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );

   // 创建SqlCommand命令,并进行预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );

   // Finally, execute the command
   int retval = cmd.ExecuteNonQuery();

   // 清除参数,以便再次使用.
   cmd.Parameters.Clear();
   if( mustCloseConnection )
    connection.Close();
   return retval;
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,将对象数组的值赋给存储过程参数.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值
  /// 示例:
  ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 给存储过程分配参数值
    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行带事务的SqlCommand.
  /// </summary>
  /// <remarks>
  /// 示例.:
  ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
  /// </remarks>
  /// <param name="transaction">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回影响的行数/returns>
  public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
  {
   return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行带事务的SqlCommand(指定参数).
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamter参数数组</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

   // 预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

   // 执行
   int retval = cmd.ExecuteNonQuery();

   // 清除参数集,以便再次使用.
   cmd.Parameters.Clear();
   return retval;
  }

  /// <summary>
  /// 执行带事务的SqlCommand(指定参数值).
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值
  /// 示例:
  ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
  /// </remarks>
  /// <param name="transaction">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回受影响的行数</returns>
  public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion ExecuteNonQuery方法结束

  #region ExecuteDataset方法

  /// <summary>
  /// 执行指定数据库连接字符串的命令,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
  {
   return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamters参数数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );

   // 创建并打开数据库连接对象,操作完成释放对象.
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    // 调用指定数据库连接字符串重载方法.
    return ExecuteDataset(connection, commandType, commandText, commandParameters);
   }
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,直接提供参数值,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值.
  /// 示例:
  ///  DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中检索存储过程参数
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 给存储过程参数分配值
    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
  {
   return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamter参数数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );

   // 预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );

   // 创建SqlDataAdapter和DataSet.
   using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
   {
    DataSet ds = new DataSet();

    // 填充DataSet.
    da.Fill(ds);

    cmd.Parameters.Clear();

    if( mustCloseConnection )
     connection.Close();

    return ds;
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,指定参数值,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输入参数和返回值.
  /// 示例.:
  ///  DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlConnection connection, string spName, params object[] parameterValues)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 比缓存中加载存储过程参数
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 给存储过程参数分配值
    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定事务的命令,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="transaction">事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
  {
   return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定事务的命令,指定参数,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamter参数数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

   // 预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

   // 创建 DataAdapter & DataSet
   using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
   {
    DataSet ds = new DataSet();
    da.Fill(ds);
    cmd.Parameters.Clear();
    return ds;
   }
  }

  /// <summary>
  /// 执行指定事务的命令,指定参数值,返回DataSet.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输入参数和返回值.
  /// 示例.:
  ///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="transaction">事务</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回一个包含结果集的DataSet</returns>
  public static DataSet ExecuteDataset(SqlTransaction transaction, string spName, params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 给存储过程参数分配值
    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion ExecuteDataset数据集命令结束

  #region ExecuteReader 数据阅读器

  /// <summary>
  /// 枚举,标识数据库连接是由SqlHelper提供还是由调用者提供
  /// </summary>
  private enum SqlConnectionOwnership
  {
   /// <summary>由SqlHelper提供连接</summary>
   Internal,
   /// <summary>由调用者提供连接</summary>
   External
  }

  /// <summary>
  /// 执行指定数据库连接对象的数据阅读器.
  /// </summary>
  /// <remarks>
  /// 如果是SqlHelper打开连接,当连接关闭DataReader也将关闭.
  /// 如果是调用都打开连接,DataReader由调用都管理.
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="transaction">一个有效的事务,或者为 'null'</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <param name="commandParameters">SqlParameters参数数组,如果没有参数则为'null'</param>
  /// <param name="connectionOwnership">标识数据库连接对象是由调用者提供还是由SqlHelper提供</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );

   bool mustCloseConnection = false;
   // 创建命令
   SqlCommand cmd = new SqlCommand();
   try
   {
    PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

    // 创建数据阅读器
    SqlDataReader dataReader;

    if (connectionOwnership == SqlConnectionOwnership.External)
    {
     dataReader = cmd.ExecuteReader();
    }
    else
    {
     dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
    }

    // 清除参数,以便再次使用..
    // HACK: There is a problem here, the output parameter values are fletched
    // when the reader is closed, so if the parameters are detached from the command
    // then the SqlReader can磘 set its values.
    // When this happen, the parameters can磘 be used again in other command.
    bool canClear = true;
    foreach(SqlParameter commandParameter in cmd.Parameters)
    {
     if (commandParameter.Direction != ParameterDirection.Input)
      canClear = false;
    }

    if (canClear)
    {
     cmd.Parameters.Clear();
    }

    return dataReader;
   }
   catch
   {
    if( mustCloseConnection )
     connection.Close();
    throw;
   }
  }

  /// <summary>
  /// 执行指定数据库连接字符串的数据阅读器.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
  {
   return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接字符串的数据阅读器,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <param name="commandParameters">SqlParamter参数数组(new SqlParameter("@prodid", 24))</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   SqlConnection connection = null;
   try
   {
    connection = new SqlConnection(connectionString);
    connection.Open();

    return ExecuteReader(connection, null, commandType, commandText, commandParameters,SqlConnectionOwnership.Internal);
   }
   catch
   {
    // If we fail to return the SqlDatReader, we need to close the connection ourselves
    if( connection != null ) connection.Close();
    throw;
   }

  }

  /// <summary>
  /// 执行指定数据库连接字符串的数据阅读器,指定参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的数据阅读器.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名或T-SQL语句</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
  {
   return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandParameters">SqlParamter参数数组</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
  }

  /// <summary>
  /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">T存储过程名</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlConnection connection, string spName, params object[] parameterValues)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return ExecuteReader(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
  {
   return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

   return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
  }

  /// <summary>
  /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReader(SqlTransaction transaction, string spName, params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    AssignParameterValues(commandParameters, parameterValues);

    return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion ExecuteReader数据阅读器

  #region ExecuteScalar 返回结果集中的第一行第一列

  /// <summary>
  /// 执行指定数据库连接字符串的命令,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
  {
   // 执行参数为空的方法
   return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,指定参数,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   // 创建并打开数据库连接对象,操作完成释放对象.
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    // 调用指定数据库连接字符串重载方法.
    return ExecuteScalar(connection, commandType, commandText, commandParameters);
   }
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,指定参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
  {
   // 执行参数为空的方法
   return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,指定参数,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );

   // 创建SqlCommand命令,并进行预处理
   SqlCommand cmd = new SqlCommand();

   bool mustCloseConnection = false;
   PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );

   // 执行SqlCommand命令,并返回结果.
   object retval = cmd.ExecuteScalar();

   // 清除参数,以便再次使用.
   cmd.Parameters.Clear();

   if( mustCloseConnection )
    connection.Close();

   return retval;
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,指定参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库事务的命令,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
  {
   // 执行参数为空的方法
   return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库事务的命令,指定参数,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

   // 创建SqlCommand命令,并进行预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

   // 执行SqlCommand命令,并返回结果.
   object retval = cmd.ExecuteScalar();

   // 清除参数,以便再次使用.
   cmd.Parameters.Clear();
   return retval;
  }

  /// <summary>
  /// 执行指定数据库事务的命令,指定参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // PPull the parameters for this stored procedure from the parameter cache ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion ExecuteScalar   

  #region ExecuteXmlReader XML阅读器
  /// <summary>
  /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
  {
   // 执行参数为空的方法
   return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );

   bool mustCloseConnection = false;
   // 创建SqlCommand命令,并进行预处理
   SqlCommand cmd = new SqlCommand();
   try
   {
    PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );

    // 执行命令
    XmlReader retval = cmd.ExecuteXmlReader();

    // 清除参数,以便再次使用.
    cmd.Parameters.Clear();

    return retval;
   }
   catch
   {
    if( mustCloseConnection )
     connection.Close();
    throw;
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称 using "FOR XML AUTO"</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
  {
   // 执行参数为空的方法
   return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
  }

  /// <summary>
  /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );

   // 创建SqlCommand命令,并进行预处理
   SqlCommand cmd = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

   // 执行命令
   XmlReader retval = cmd.ExecuteXmlReader();

   // 清除参数,以便再次使用.
   cmd.Parameters.Clear();
   return retval;
  }

  /// <summary>
  /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  XmlReader r = ExecuteXmlReader(trans, "GetOrders", 24, 36);
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  /// <returns>返回一个包含结果集的DataSet.</returns>
  public static XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    // 没有参数值
    return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion ExecuteXmlReader 阅读器结束

  #region FillDataset 填充数据集
  /// <summary>
  /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)</param>
  public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( dataSet == null ) throw new ArgumentNullException( "dataSet" );

   // 创建并打开数据库连接对象,操作完成释放对象.
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    // 调用指定数据库连接字符串重载方法.
    FillDataset(connection, commandType, commandText, dataSet, tableNames);
   }
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.指定命令参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  public static void FillDataset(string connectionString, CommandType commandType,
   string commandText, DataSet dataSet, string[] tableNames,
   params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
   // 创建并打开数据库连接对象,操作完成释放对象.
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    // 调用指定数据库连接字符串重载方法.
    FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
   }
  }

  /// <summary>
  /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集,指定存储过程参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, 24);
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  public static void FillDataset(string connectionString, string spName,
   DataSet dataSet, string[] tableNames,
   params object[] parameterValues)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
   // 创建并打开数据库连接对象,操作完成释放对象.
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    connection.Open();

    // 调用指定数据库连接字符串重载方法.
    FillDataset (connection, spName, dataSet, tableNames, parameterValues);
   }
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,映射数据表并填充数据集.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  public static void FillDataset(SqlConnection connection, CommandType commandType,
   string commandText, DataSet dataSet, string[] tableNames)
  {
   FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  public static void FillDataset(SqlConnection connection, CommandType commandType,
   string commandText, DataSet dataSet, string[] tableNames,
   params SqlParameter[] commandParameters)
  {
   FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
  }

  /// <summary>
  /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定存储过程参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  FillDataset(conn, "GetOrders", ds, new string[] {"orders"}, 24, 36);
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  public static void FillDataset(SqlConnection connection, string spName,
   DataSet dataSet, string[] tableNames,
   params object[] parameterValues)
  {
   if ( connection == null ) throw new ArgumentNullException( "connection" );
   if (dataSet == null ) throw new ArgumentNullException( "dataSet" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
   }
   else
   {
    // 没有参数值
    FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
   }
  }

  /// <summary>
  /// 执行指定数据库事务的命令,映射数据表并填充数据集.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  public static void FillDataset(SqlTransaction transaction, CommandType commandType,
   string commandText,
   DataSet dataSet, string[] tableNames)
  {
   FillDataset (transaction, commandType, commandText, dataSet, tableNames, null);
  }

  /// <summary>
  /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  public static void FillDataset(SqlTransaction transaction, CommandType commandType,
   string commandText, DataSet dataSet, string[] tableNames,
   params SqlParameter[] commandParameters)
  {
   FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
  }

  /// <summary>
  /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定存储过程参数值.
  /// </summary>
  /// <remarks>
  /// 此方法不提供访问存储过程输出参数和返回值参数.
  ///
  /// 示例:
  ///  FillDataset(trans, "GetOrders", ds, new string[]{"orders"}, 24, 36);
  /// </remarks>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
  public static void FillDataset(SqlTransaction transaction, string spName,
   DataSet dataSet, string[] tableNames,
   params object[] parameterValues)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果有参数值
   if ((parameterValues != null) && (parameterValues.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 给存储过程参数赋值
    AssignParameterValues(commandParameters, parameterValues);

    // 调用重载方法
    FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
   }
   else
   {
    // 没有参数值
    FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
   }
  }

  /// <summary>
  /// [私有方法][内部调用]执行指定数据库连接对象/事务的命令,映射数据表并填充数据集,DataSet/TableNames/SqlParameters.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  FillDataset(conn, trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="transaction">一个有效的连接事务</param>
  /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
  /// <param name="commandText">存储过程名称或T-SQL语句</param>
  /// <param name="dataSet">要填充结果集的DataSet实例</param>
  /// <param name="tableNames">表映射的数据表数组
  /// 用户定义的表名 (可有是实际的表名.)
  /// </param>
  /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
  private static void FillDataset(SqlConnection connection, SqlTransaction transaction, CommandType commandType,
   string commandText, DataSet dataSet, string[] tableNames,
   params SqlParameter[] commandParameters)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( dataSet == null ) throw new ArgumentNullException( "dataSet" );

   // 创建SqlCommand命令,并进行预处理
   SqlCommand command = new SqlCommand();
   bool mustCloseConnection = false;
   PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );

   // 执行命令
   using( SqlDataAdapter dataAdapter = new SqlDataAdapter(command) )
   {

    // 追加表映射
    if (tableNames != null && tableNames.Length > )
    {
     string tableName = "Table";
     for (int index=; index < tableNames.Length; index++)
     {
      if( tableNames[index] == null || tableNames[index].Length ==  ) throw new ArgumentException( "The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames" );
      dataAdapter.TableMappings.Add(tableName, tableNames[index]);
      tableName += (index + ).ToString();
     }
    }

    // 填充数据集使用默认表名称
    dataAdapter.Fill(dataSet);

    // 清除参数,以便再次使用.
    command.Parameters.Clear();
   }

   if( mustCloseConnection )
    connection.Close();
  }
  #endregion

  #region UpdateDataset 更新数据集
  /// <summary>
  /// 执行数据集更新到数据库,指定inserted, updated, or deleted命令.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");
  /// </remarks>
  /// <param name="insertCommand">[追加记录]一个有效的T-SQL语句或存储过程</param>
  /// <param name="deleteCommand">[删除记录]一个有效的T-SQL语句或存储过程</param>
  /// <param name="updateCommand">[更新记录]一个有效的T-SQL语句或存储过程</param>
  /// <param name="dataSet">要更新到数据库的DataSet</param>
  /// <param name="tableName">要更新到数据库的DataTable</param>
  public static void UpdateDataset(SqlCommand insertCommand, SqlCommand deleteCommand, SqlCommand updateCommand, DataSet dataSet, string tableName)
  {
   if( insertCommand == null ) throw new ArgumentNullException( "insertCommand" );
   if( deleteCommand == null ) throw new ArgumentNullException( "deleteCommand" );
   if( updateCommand == null ) throw new ArgumentNullException( "updateCommand" );
   if( tableName == null || tableName.Length ==  ) throw new ArgumentNullException( "tableName" );

   // 创建SqlDataAdapter,当操作完成后释放.
   using (SqlDataAdapter dataAdapter = new SqlDataAdapter())
   {
    // 设置数据适配器命令
    dataAdapter.UpdateCommand = updateCommand;
    dataAdapter.InsertCommand = insertCommand;
    dataAdapter.DeleteCommand = deleteCommand;

    // 更新数据集改变到数据库
    dataAdapter.Update (dataSet, tableName);

    // 提交所有改变到数据集.
    dataSet.AcceptChanges();
   }
  }
  #endregion

  #region CreateCommand 创建一条SqlCommand命令
  /// <summary>
  /// 创建SqlCommand命令,指定数据库连接对象,存储过程名和参数.
  /// </summary>
  /// <remarks>
  /// 示例:
  ///  SqlCommand command = CreateCommand(conn, "AddCustomer", "CustomerID", "CustomerName");
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="sourceColumns">源表的列名称数组</param>
  /// <returns>返回SqlCommand命令</returns>
  public static SqlCommand CreateCommand(SqlConnection connection, string spName, params string[] sourceColumns)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 创建命令
   SqlCommand cmd = new SqlCommand( spName, connection );
   cmd.CommandType = CommandType.StoredProcedure;

   // 如果有参数值
   if ((sourceColumns != null) && (sourceColumns.Length > ))
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 将源表的列到映射到DataSet命令中.
    for (int index=; index < sourceColumns.Length; index++)
     commandParameters[index].SourceColumn = sourceColumns[index];

    // Attach the discovered parameters to the SqlCommand object
    AttachParameters (cmd, commandParameters);
   }

   return cmd;
  }
  #endregion

  #region ExecuteNonQueryTypedParams 类型化参数(DataRow)
  /// <summary>
  /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回受影响的行数.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if (dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回受影响的行数.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQueryTypedParams(SqlConnection connection, String spName, DataRow dataRow)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if (dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回受影响的行数.
  /// </summary>
  /// <param name="transaction">一个有效的连接事务 object</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回影响的行数</returns>
  public static int ExecuteNonQueryTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // Sf the row has values, the store procedure parameters must be initialized
   if (dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
   }
  }
  #endregion

  #region ExecuteDatasetTypedParams 类型化参数(DataRow)
  /// <summary>
  /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataSet.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回一个包含结果集的DataSet.</returns>
  public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   //如果row有值,存储过程必须初始化.
   if ( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataSet.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回一个包含结果集的DataSet.</returns>
  ///
  public static DataSet ExecuteDatasetTypedParams(SqlConnection connection, String spName, DataRow dataRow)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回DataSet.
  /// </summary>
  /// <param name="transaction">一个有效的连接事务 object</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回一个包含结果集的DataSet.</returns>
  public static DataSet ExecuteDatasetTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
   }
  }

  #endregion

  #region ExecuteReaderTypedParams 类型化参数(DataRow)
  /// <summary>
  /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataReader.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if ( dataRow != null && dataRow.ItemArray.Length >  )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataReader.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回DataReader.
  /// </summary>
  /// <param name="transaction">一个有效的连接事务 object</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回包含结果集的SqlDataReader</returns>
  public static SqlDataReader ExecuteReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length >  )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
   }
  }
  #endregion

  #region ExecuteScalarTypedParams 类型化参数(DataRow)
  /// <summary>
  /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalarTypedParams(SqlConnection connection, String spName, DataRow dataRow)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
  /// </summary>
  /// <param name="transaction">一个有效的连接事务 object</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回结果集中的第一行第一列</returns>
  public static object ExecuteScalarTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
   }
  }
  #endregion

  #region ExecuteXmlReaderTypedParams 类型化参数(DataRow)
  /// <summary>
  /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
   }
  }

  /// <summary>
  /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
  /// </summary>
  /// <param name="transaction">一个有效的连接事务 object</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="dataRow">使用DataRow作为参数值</param>
  /// <returns>返回XmlReader结果集对象.</returns>
  public static XmlReader ExecuteXmlReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
  {
   if( transaction == null ) throw new ArgumentNullException( "transaction" );
   if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   // 如果row有值,存储过程必须初始化.
   if( dataRow != null && dataRow.ItemArray.Length > )
   {
    // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
    SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);

    // 分配参数值
    AssignParameterValues(commandParameters, dataRow);

    return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
   }
   else
   {
    return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
   }
  }
  #endregion

 }
//////////////////////////////////////////////////////////////////////////////////可以放入另一个类SqlHelperParameterCache
 /// <summary>
 /// SqlHelperParameterCache提供缓存存储过程参数,并能够在运行时从存储过程中探索参数.
 /// </summary>
 public sealed class SqlHelperParameterCache
 {
  #region 私有方法,字段,构造函数
  // 私有构造函数,妨止类被实例化.
  private SqlHelperParameterCache() {}

  // 这个方法要注意
  private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());

  /// <summary>
  /// 探索运行时的存储过程,返回SqlParameter参数数组.
  /// 初始化参数值为 DBNull.Value.
  /// </summary>
  /// <param name="connection">一个有效的数据库连接</param>
  /// <param name="spName">存储过程名称</param>
  /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
  /// <returns>返回SqlParameter参数数组</returns>
  private static SqlParameter[] DiscoverSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   SqlCommand cmd = new SqlCommand(spName, connection);
   cmd.CommandType = CommandType.StoredProcedure;

   connection.Open();
   // 检索cmd指定的存储过程的参数信息,并填充到cmd的Parameters参数集中.
   SqlCommandBuilder.DeriveParameters(cmd);
   connection.Close();
   // 如果不包含返回值参数,将参数集中的每一个参数删除.
   if (!includeReturnValueParameter)
   {
    cmd.Parameters.RemoveAt();
   }

   // 创建参数数组
   SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];
   // 将cmd的Parameters参数集复制到discoveredParameters数组.
   cmd.Parameters.CopyTo(discoveredParameters, );

   // 初始化参数值为 DBNull.Value.
   foreach (SqlParameter discoveredParameter in discoveredParameters)
   {
    discoveredParameter.Value = DBNull.Value;
   }
   return discoveredParameters;
  }

  /// <summary>
  /// SqlParameter参数数组的深层拷贝.
  /// </summary>
  /// <param name="originalParameters">原始参数数组</param>
  /// <returns>返回一个同样的参数数组</returns>
  private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
  {
   SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];

   for (int i = , j = originalParameters.Length; i < j; i++)
   {
    clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
   }

   return clonedParameters;
  }

  #endregion 私有方法,字段,构造函数结束

  #region 缓存方法

  /// <summary>
  /// 追加参数数组到缓存.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符串</param>
  /// <param name="commandText">存储过程名或SQL语句</param>
  /// <param name="commandParameters">要缓存的参数数组</param>
  public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( commandText == null || commandText.Length ==  ) throw new ArgumentNullException( "commandText" );

   string hashKey = connectionString + ":" + commandText;

   paramCache[hashKey] = commandParameters;
  }

  /// <summary>
  /// 从缓存中获取参数数组.
  /// </summary>
  /// <param name="connectionString">一个有效的数据库连接字符</param>
  /// <param name="commandText">存储过程名或SQL语句</param>
  /// <returns>参数数组</returns>
  public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( commandText == null || commandText.Length ==  ) throw new ArgumentNullException( "commandText" );

   string hashKey = connectionString + ":" + commandText;

   SqlParameter[] cachedParameters = paramCache[hashKey] as SqlParameter[];
   if (cachedParameters == null)
   {
    return null;
   }
   else
   {
    return CloneParameters(cachedParameters);
   }
  }

  #endregion 缓存方法结束

  #region 检索指定的存储过程的参数集

  /// <summary>
  /// 返回指定的存储过程的参数集
  /// </summary>
  /// <remarks>
  /// 这个方法将查询数据库,并将信息存储到缓存.
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符</param>
  /// <param name="spName">存储过程名</param>
  /// <returns>返回SqlParameter参数数组</returns>
  public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
  {
   return GetSpParameterSet(connectionString, spName, false);
  }

  /// <summary>
  /// 返回指定的存储过程的参数集
  /// </summary>
  /// <remarks>
  /// 这个方法将查询数据库,并将信息存储到缓存.
  /// </remarks>
  /// <param name="connectionString">一个有效的数据库连接字符.</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
  /// <returns>返回SqlParameter参数数组</returns>
  public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
  {
   if( connectionString == null || connectionString.Length ==  ) throw new ArgumentNullException( "connectionString" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   using(SqlConnection connection = new SqlConnection(connectionString))
   {
    return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
   }
  }

  /// <summary>
  /// [内部]返回指定的存储过程的参数集(使用连接对象).
  /// </summary>
  /// <remarks>
  /// 这个方法将查询数据库,并将信息存储到缓存.
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接字符</param>
  /// <param name="spName">存储过程名</param>
  /// <returns>返回SqlParameter参数数组</returns>
  internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName)
  {
   return GetSpParameterSet(connection, spName, false);
  }

  /// <summary>
  /// [内部]返回指定的存储过程的参数集(使用连接对象)
  /// </summary>
  /// <remarks>
  /// 这个方法将查询数据库,并将信息存储到缓存.
  /// </remarks>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="includeReturnValueParameter">
  /// 是否包含返回值参数
  /// </param>
  /// <returns>返回SqlParameter参数数组</returns>
  internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   using (SqlConnection clonedConnection = (SqlConnection)((ICloneable)connection).Clone())
   {
    return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
   }
  }

  /// <summary>
  /// [私有]返回指定的存储过程的参数集(使用连接对象)
  /// </summary>
  /// <param name="connection">一个有效的数据库连接对象</param>
  /// <param name="spName">存储过程名</param>
  /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
  /// <returns>返回SqlParameter参数数组</returns>
  private static SqlParameter[] GetSpParameterSetInternal(SqlConnection connection, string spName, bool includeReturnValueParameter)
  {
   if( connection == null ) throw new ArgumentNullException( "connection" );
   if( spName == null || spName.Length ==  ) throw new ArgumentNullException( "spName" );

   string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");

   SqlParameter[] cachedParameters;

   cachedParameters = paramCache[hashKey] as SqlParameter[];
   if (cachedParameters == null)
   {
    SqlParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
    paramCache[hashKey] = spParameters;
    cachedParameters = spParameters;
   }

   return CloneParameters(cachedParameters);
  }

  #endregion 参数集检索结束

 }
}