编码过程中使用SqlDataReader 来操作数据库时,你是否每次在调用完你的数据库方法后,再手动调用方法或写代码关闭数据库联接呢？(呵呵　我以前是这样做的　见笑)
下面的方法可以完成解决此问题了,cmd.ExecuteReader的参数CommandBehavior.CloseConnection会自动帮你关闭与之相关联的conn

 public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
      {

            SqlCommand cmd = new SqlCommand();

            SqlConnection conn = new SqlConnection(connectionString);

          try
            {

                PRepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);

                   // 给cmd.ExecuteReader加上参数CommandBehavior.CloseConnection会在cmd.ExecuteReader执行完后自动关闭与之相关联的conn
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
               
                cmd.Parameters.Clear();

                return rdr;

            }

            catch
            {

                conn.Close();

                throw;

            }

       }
http://www.cnblogs.com/abeen/archive/2006/12/19/597039.html