创建一个控件:
page_load..
{
  creatememoLbl();
}private void CreateMemoLbl()
{
 Label LblMemo=new Label();
LblMemo.ID="LblMemo";
 LblMemo.Width=400;
 LblMemo.Height=200;
 Panel1.Controls.Add(LblMemo);
}引用:
  private void Test()
{
...................
  ((Label)(Panel1.FindControl("LblMemo"))).Text=objDs.Tables[0].Rows[0][4].ToString(); 
...
....
}
错误:
异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。源错误: 
行 117: catch
行 118: {
行 119: ((Label)(Panel1.FindControl("LblMemo"))).Text=objDs.Tables[0].Rows[0][4].ToString();
行 120: //Response.Redirect("error2.html");
行 121: }