反射+泛型+缓存 ASP.NET的数据层通用类

 using System;
 using System.Collections.Generic;
 using System.Text;
 using System.Reflection ;
 using System.Data ;
 using BaiChang.HealBlog.Model ;
 using System.Data.SqlClient;
 using BaiChang.SqlDBUtility;

 namespace BaiChang.Middle.Front
 {
     public  class DataAccess<T>where T:new()
     {
         #region Main Part

         public static DataAccess<T> GetDataAccess()
         {
             string name = "DataAccess" + typeof(T).Name;
             DataAccess<T> tObj = Utils.CurrentPage.Cache[name] as DataAccess<T>;

             object obj = new object();
             if (tObj == null)
             {
                 Utils.CurrentPage.Cache[name] = typeof(DataAccess < T>).Assembly.CreateInstance(typeof(DataAccess<T>).Name);
                 tObj = Utils.CurrentPage.Cache[name] as DataAccess<T>;
             }
             return tObj;
         }

         public static string ToSetString(string name)
         {
             string formate = "{0}={1}";
             return string.Format(formate, name, name);
         }

         public static List<T> ToModel(SqlDataReader reader)
         {
             Dictionary<string, PropertyInfo> ps = new Dictionary<string, PropertyInfo>();
             foreach (PropertyInfo p in typeof (T).GetProperties ())
             {
                 ps.Add(p.Name, p);
             }

             List<T> ms=new List<T> ();
             while (reader.Read())
             {
                 T m = new T();
                 object[] objs = null;
                 int count = reader.GetValues(objs);
                 int i = ;
                 foreach (object o in objs)
                 {
                     ps[reader.GetName(i)].SetValue(m, o, null);
                     i++;
                 }
                 ms.Add(m);
             }
             return ms;
         }
         #region Properties
         //当前实体类型
         Type entityType;
         Type type
         {
             get
             {
                 if(entityType ==null)
                 entityType = typeof(T);
                 return entityType;
             }
         }

         //实体的所有属性
         PropertyInfo[] propertyInfos;
         PropertyInfo[] pros
         {
             get
             {
                 if (propertyInfos == null) propertyInfos = this.type.GetProperties();
                 return propertyInfos;
             }
         }

         //相对应的表名
         string _tableName=string.Empty ;
         string tableName
         {
             get
             {
                 if (_tableName == string.Empty)
                 {
                     string className = typeof(T).Name;

                     switch (className)
                     {
                         case "Users":
                         case "Role_Node_Permissions":
                             _tableName = "PE_" + className;
                         default:
                             _tableName = "HB_" + className;
                     }
                 }
             }
         }
         #endregion
         #endregion

         #region  成员方法

         /// <summary>
         /// 得到最大ID
         /// </summary>
         public int GetMaxId()
         {
             return DbHelperSQL.GetMaxID(pros[].Name , tableName);
         }

         /// <summary>
         /// 得到最大值
         /// </summary>

         /// <summary>
         /// 是否存在该记录
         /// </summary>
         public bool Exists(int ID)
         {
             StringBuilder strSql = new StringBuilder();
             strSql.Append("select count(1) from ");
             strSql.Append(tableName);
             strSql.Append(" where ");
             strSql.Append(ToSetString(pros[].Name));
             SqlParameter[] parameters = {
                     new SqlParameter("@"+pros[].Name, SqlDbType.Int,)};
             parameters[].Value = ID;

             return DbHelperSQL.Exists(strSql.ToString(), parameters);
         }

         /// <summary>
         /// 增加一条数据
         /// </summary>
         public int Add(T model)
         {
             StringBuilder strSql = new StringBuilder();

             strSql .Append ("insert into ");
             strSql .Append (tableName );
             strSql.Append(" (");

             //生成XXXvalues(XXX)
             int i=;
             foreach (PropertyInfo p in pros)
             {
                 strSql .Append (p.Name );
                 if (i != pros.Length)
                     strSql.Append(",");
                 i++;
             }
             strSql.Append(") values (");
             i = ;
             foreach (PropertyInfo p in pros)
             {
                 strSql.Append("@");
                 strSql.Append(p.Name);
                 if (i != pros.Length)
                     strSql.Append(",");
                 i++;
             }
             strSql.Append(");select @@IDENTITY");

             //生成sqlparameters
             List<SqlParameter> sqlpars = new List<SqlParameter>();
             foreach (PropertyInfo p in pros)
             {
                 SqlParameter sp = new SqlParameter("@" + p.Name, p.GetValue(model, null));
                 sqlpars.Add(sp);
             }
             object obj = DbHelperSQL.GetSingle(strSql.ToString(), sqlpars .ToArray ());
             if (obj == null)
             {
                 return ;
             }
             else
             {
                 return Convert.ToInt32(obj);
             }
         }

         /// <summary>
         /// 更新一条数据
         /// </summary>
         public void Update(T model)
         {
             StringBuilder strSql = new StringBuilder();
             strSql.Append("update ");
             strSql .Append (tableName );
             strSql .Append (" set ");
             int i=;
             foreach (PropertyInfo p in pros)
             {
                 strSql.Append(ToSetString(p.Name));
                 if(i!=pros.Length )
                     strSql .Append (",");
                 i++;
             }
             strSql.Append(" where ");
             strSql.Append(ToSetString(pros[].Name));
             //生成sqlparameters
             List<SqlParameter> sqlpars = new List<SqlParameter>();
             foreach (PropertyInfo p in pros)
             {
                 SqlParameter sp = new SqlParameter("@" + p.Name, p.GetValue(model, null));
                 sqlpars.Add(sp);
             }

             DbHelperSQL.ExecuteSql(strSql.ToString(), sqlpars .ToArray());
         }

         /// <summary>
         /// 删除一条数据
         /// </summary>
         public void Delete(int ID)
         {

             StringBuilder strSql = new StringBuilder();
             strSql.Append("delete from ");
             strSql.Append(tableName);
             strSql.Append(" where ");
             strSql.Append(ToSetString(pros[].Name));
             SqlParameter[] parameters = {
                     new SqlParameter("@"+pros [].Name, SqlDbType.Int,)};
             parameters[].Value = ID;

             DbHelperSQL.ExecuteSql(strSql.ToString(), parameters);
         }

         /// <summary>
         /// 得到一个对象实体
         /// </summary>
         public T GetModel(int ID)
         {

             StringBuilder strSql = new StringBuilder();
             strSql.Append("select  top 1 ");
             int i=;
             foreach (PropertyInfo p in pros)
             {
                 strSql.Append(ToSetString(p.Name));
                 if(i!=pros.Length )
                     strSql .Append (",");
             }
             strSql .Append (tableName );
             strSql.Append(" where  ");
             strSql.Append(ToSetString(pros[].Name));
             SqlParameter[] parameters = {
                     new SqlParameter("@"+pros[].Name, SqlDbType.Int,)};
             parameters[].Value = ID;
             List<T> ms;
             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString (), parameters))
             {
                  ms= ToModel(reader);
                 reader.Close();
             }
             if (ms.Count > ) return ms[];
             else return default (T);
         }

         /// <summary>
         /// 获得数据列表
         /// </summary>
         public List<T> GetList(string strWhere)
         {
             StringBuilder strSql = new StringBuilder();
             strSql.Append("select * ");
             strSql.Append(" FROM ");
             strSql.Append(tableName);
             if (strWhere.Trim() != "")
             {
                 strSql.Append(" where " + strWhere);
             }

             List<T> ms;
             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString ()))
             {
                 ms = ToModel(reader);
                 reader.Close();
             }
             if (ms.Count > ) return ms;
             else return null;
         }

         /// <summary>
         /// 获得前几行数据
         /// </summary>
         public List<T> GetList(int Top, string strWhere, string filedOrder)
         {
             StringBuilder strSql = new StringBuilder();
             strSql.Append("select ");
             if (Top > )
             {
                 strSql.Append(" top " + Top.ToString());
             }
             strSql.Append(" * ");
             strSql.Append(" FROM  ");
             strSql.Append(tableName);
             if (strWhere.Trim() != "")
             {
                 strSql.Append(" where " + strWhere);
             }
             strSql.Append(" order by " + filedOrder);
                         List<T> ms;
             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString ()))
             {
                 ms = ToModel(reader);
                 reader.Close();
             }
             if (ms.Count > ) return ms;
             else return null;
         }

          ///<summary>
          ///分页获取数据列表
          ///</summary>
         public List<T> GetList(int PageSize,int PageIndex,string strWhere)
         {
             List<T> ms=GetList(strWhere);
             int startIndex=, endIndex=;
             Utils.GetPageArea(ref startIndex, ref endIndex, PageIndex, PageSize, ms.Count);
             List<T> result = new List<T>();
             for (int i = startIndex; i <= endIndex; i++)
             {
                 result.Add(ms[i]);
             }
             return result;
         }

         #endregion  成员方法

     }
 }

一点想法+一点尝试
还有些问题有待解决^_^

作者：today4king

转载：http://www.cnblogs.com/jinzhao/archive/2009/07/24/1530213.html