title: How to prevent css missing when exporting some html to excel file?
body: <p>I am exporting an html table to excel file successfully using following code</p>
  
  <pre><code>    public void exportGridToExcel(Control ctl)
      {
          string attachment = "attachment; filename=etrack_excel_export.xls";
          HttpContext.Current.Response.ClearContent();
          HttpContext.Current.Response.AddHeader("content-disposition", attachment);
          HttpContext.Current.Response.ContentType = "application/ms-excel";
          StringWriter stw = new StringWriter();
          HtmlTextWriter htextw = new HtmlTextWriter(stw);
  
          ctl.RenderControl(htextw);
          HttpContext.Current.Response.Write(stw.ToString());
          HttpContext.Current.Response.End();
      }
  </code></pre>
  
  <p>The issue is that after exportation all css I have applied to the table is missing in the excel file , How can I prevent the css from missing?</p>