sql异步执行

 /// <summary>  
/// 按钮事件 异步执行  
/// </summary>  
/// <param name="sender"></param>  
/// <param name="e"></param>  
private void button4_Click(object sender, EventArgs e)  
{  
    string strSql = "SELECT c1 ,c2 FROM  T1;" +  
                    "WAITFOR DELAY '0:0:3';";  
    AsyncExecuteNonQuery(strSql, CallbackAsyncExecuteNonQuery);  
}  
  
// <summary>  
/// 异步执行SQL。   
/// </summary>  
/// <param name="sqlText">要执行的SQLText</param>  
/// <param name="callBack">回执行监控事件</param>  
public static void AsyncExecuteNonQuery(string sqlText, AsyncCallback callBack)  
{  
    //关闭数据库连接要在callback中关闭，因为是异步操作  
    SqlConnection connection = null;  
    try  
    {  
        connection = new SqlConnection();  
        connection.ConnectionString = "Data Source=192.168.1.15;Initial Catalog=TestDB;user id=sa;password=123;Max Pool Size=200;Min Pool Size=5;Pooling=true;Connection Timeout=50;Asynchronous Processing=true";  
        SqlCommand cmd = connection.CreateCommand();  
        cmd.CommandType = CommandType.Text;  
        cmd.CommandText = sqlText;  
        connection.Open();  
        cmd.BeginExecuteNonQuery(callBack, cmd); //开始执行SQL语句  
    }  
    catch (Exception ex)  
    {  
        if (connection != null)  
        {  
            connection.Close();  
        }  
    }  
}  
/// <summary>  
///  执行异步SQL 回调方法   
/// </summary>  
/// <param name="callBack"></param>  
public static void CallbackAsyncExecuteNonQuery(IAsyncResult callBack)  
{  
    SqlCommand cmm = null;  
    try  
    {  
        cmm = (SqlCommand)callBack.AsyncState;  
        if (cmm == null)  
        {  
            return;  
        }  
        cmm.EndExecuteNonQuery(callBack); //执行完毕  
    }  
    catch (Exception ex)  
    {  
        if (cmm != null)  
        {  
            //异步执行SQL异常  
            cmm.Dispose();  
        }  
        else  
        {  
            //异步执行SQL异常  
        }  
    }  
    finally  
    {  
        if (cmm != null && cmm.Connection != null && cmm.Connection.State != ConnectionState.Closed)  
        {  
            cmm.Dispose();  
            cmm.Connection.Close();  
        }  
    }  
}