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();
        }
    }
}