导出excel的乱码问题，

[osborne]

用以下代码导出datagrid,有些文件正常，有些会是乱码，是啥问题？？
所有的导出都是经过这个文件导出的．

HttpContext.Current.Response.AppendHeader("Content-Disposition","attachment;filename=export.xls");
HttpContext.Current.Response.Charset ="GB2312";
HttpContext.Current.Response.ContentEncoding =System.Text.Encoding.Default;
HttpContext.Current.Response.ContentType ="application/vnd.ms-excel";
/****image/JPEG;text/HTML;image/GIF;vnd.ms-excel/msword****/
myDataGrid.EnableViewState =false;
System.IO.StringWriter tw = new System.IO.StringWriter() ;
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter (tw);
myDataGrid.RenderControl(hw);
HttpContext.Current.Response.Write(tw.ToString());
HttpContext.Current.Response.End();

[acewang]

试：HttpContext.Current.Response.Charset ="UTF-8";

[osborne]

已試過, 沒用!
有些導出文件是好的, 有些不行

[felixl]

System.Text.Encoding.UTF-8
这样试了吗？