C# 使用Action异步问题

[david_88888]

代码如下:
Action myAction = new Action(myThreadMOCTG);
IAsyncResult myResult = myAction.BeginInvoke(new AsyncCallback(CallBack), null);
if(myResult.IsCompleted) {
try
{

if (myMOCTGGS.MOCTGGS.Rows.Count == 0)
{
MessageBox.Show("没有查询到任何数据");
}
else
{
RPT.rptMOCTGGS myRpt = new RPT.rptMOCTGGS();
myRpt.SetDataSource(myMOCTGGS);
frmRptFrame myFrame = new frmRptFrame();
myFrame.SetReportDoument = myRpt;
myFrame.SetFormText = "工单核对表";
myFrame.Show();
}
}
catch (Exception Ex)
{
MessageBox.Show(Ex.Message.ToString());
}
finally
{
ANDON_WIN.CommForm.ProgramProcessing.Hide();
btnQuery.Enabled = true;
}
}


void CallBack(IAsyncResult ar)
{


}

private void myThreadMOCTG()
{
myMOCTGGS = bllMake.queryMOCTGGS(strMD001, strBeginDate, strEndDate);
}
异步调用myThreadMOCTG()这个方法比较耗时，完成之后就把查询出的数据加载进报表，但是如何判断异步是否执行完成，用红色字的部分,谢谢了！！