原来可以这样得到控件的html文本

 

   System.IO.StringWriter oStringWriter  =   new  System.IO.StringWriter(); 
   System.Web.UI.HtmlTextWriter oHtmlTextWriter  =   new  System.Web.UI.HtmlTextWriter(oStringWriter); 
    this .DataGrid1.RenderControl(oHtmlTextWriter); 
   Response.Write(oStringWriter.ToString()); 
   Response.End();