Response.AddHeader("Content-Disposition", "attachment; filename=test"); 
        //Response.Charset = "UTF-8"; 
Response.Charset = "Unicode"; 
        Response.ContentType = "application/vnd.ms-excel"; 
        Response.Charset = "";          
        System.IO.StringWriter tw = new System.IO.StringWriter(); 
        System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw); 
        this.DataGrid.RenderControl(hw); 
        Response.Write(tw.ToString()); 
        Response.End();