制作ado开发辅助工具类SqlHelper

  public static class SqlHelper
     {
         //通过配置文件获取连接字符创
         private static readonly string constr = ConfigurationManager.ConnectionStrings["str"].ConnectionString;
         /// <summary>
         /// 执行增,删,改的方法
         /// </summary>
         /// <param name="sql">要执行的sql语句</param>
         /// <param name="spt">参数化查询的参数</param>
         /// <returns>影响的行数</returns>
         public static int ExecuteNonquery(string sql, params SqlParameter[] spt)
         {
             using (SqlConnection con = new SqlConnection(constr))
             {
                 using (SqlCommand cmd = new SqlCommand(sql, con))
                 {
                     con.Open();
                     if (spt != null)
                     {
                         cmd.Parameters.AddRange(spt);
                     }
                     return cmd.ExecuteNonQuery();
                 }
             }
         }
         /// <summary>
         /// 执行返回一行一列数据的方法
         /// </summary>
         /// <param name="sql"></param>
         /// <param name="spt"></param>
         /// <returns></returns>
         public static object ExecuteScalar(string sql, params SqlParameter[] spt)
         {
             using (SqlConnection con = new SqlConnection(constr))
             {
                 using (SqlCommand cmd = new SqlCommand(sql, con))
                 {
                     con.Open();
                     if (spt != null)
                     {
                         cmd.Parameters.AddRange(spt);
                     }
                     return cmd.ExecuteScalar();
                 }
             }
         }
         /// <summary>
         /// 执行查询语句的方法
         /// </summary>
         /// <param name="sql"></param>
         /// <param name="spt"></param>
         /// <returns>SqlDataReader类型</returns>
         public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] spt)
         {
             SqlConnection con = new SqlConnection(constr);
             using (SqlCommand cmd = new SqlCommand(sql, con))
             {
                 if (spt != null)
                 {
                     cmd.Parameters.AddRange(spt);
                 }

                 try
                 {
                     con.Open();
                     return cmd.ExecuteReader(CommandBehavior.CloseConnection);
                 }
                 catch (Exception)
                 {
                     con.Close();
                     con.Dispose();
                     throw;
                 }
             }
         }
         /// <summary>
         /// 用到DataAdapter的方法,
         /// </summary>
         /// <param name="sql"></param>
         /// <param name="spt"></param>
         /// <returns>DataTable类型</returns>
         public static DataTable ExecuteAdapter(string sql, params SqlParameter[] spt)
         {
             DataTable ds = new DataTable();
             using (SqlDataAdapter da = new SqlDataAdapter(sql, constr))
             {
                 if (spt != null)
                 {
                     da.SelectCommand.Parameters.AddRange(spt);
                 }
                 da.Fill(ds);
             }
             return ds;

         }
     }