asp.net导出excel乱码问题

this.BonusList.DataSource = ds;
this.BonusList.DataBind();

// Response.AddHeader("Content-Type", "application/vnd.ms-excel");
// Response.AddHeader("Content-Disposition", "attachment;filename=[Month-Detail]-"+FileName.ToString()+"");
// Response.Charset = "";
// ResponseEncoding="utf-8";//以此编码模式导出才不会出现乱码

Response.Clear();
Response.Buffer = true;
Response.Charset = "GB2312";
Response.AddHeader("Content-Disposition", "attachment;filename=[Month-Detail]-"+FileName.ToString()+"");
// 如果设置为 GetEncoding("GB2312");导出的文件将会出现乱码！！！
Response.ContentEncoding = System.Text.Encoding.UTF7;
Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。

//关闭 ViewState
EnableViewState = false;
System.IO.StringWriter tw = new System.IO.StringWriter();//将信息写入字符串
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);//在WEB窗体页上写出一系列连续的HTML特定字符和文本。