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using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.ComponentModel;
namespace SQLHelper
{
 /// <summary>
 /// Class1 µÄժҪ˵Ã÷¡£
 /// </summary>
 public class SQLHelper
 {
  // Á¬½ÓÊý¾ÝÔ´
  private SqlConnection myConnection;
  private readonly string RETURNVALUE = "RETURNVALUE";
  /// <summary>
  /// ´ò¿ªÊý¾Ý¿âÁ¬½Ó.
  /// </summary>
  private void Open()
  {
   // ´ò¿ªÊý¾Ý¿âÁ¬½Ó
   if (myConnection == null)
   {
    myConnection = new SqlConnection(ConfigurationSettings.AppSettings["SQLCONNECTIONSTRING"].ToString());    
   }    
   if(myConnection.State == ConnectionState.Closed)
   {  
    try
    {
     ///´ò¿ªÊý¾Ý¿âÁ¬½Ó
     myConnection.Open();
    }
    catch(Exception ex)
    {
     SystemError.SystemLog(ex.Message);
    }
    finally
    {
     ///¹Ø±ÕÒѾ­´ò¿ªµÄÊý¾Ý¿âÁ¬½Ó    
    }
   }
  }
  /// <summary>
  /// ¹Ø±ÕÊý¾Ý¿âÁ¬½Ó
  /// </summary>
  public void Close()
  {
   ///ÅжÏÁ¬½ÓÊÇ·ñÒѾ­´´½¨
   if(myConnection != null)
   {
    ///ÅжÏÁ¬½ÓµÄ״̬ÊÇ·ñ´ò¿ª
    if(myConnection.State == ConnectionState.Open)
    {
     myConnection.Close();
   &