问在asp.net mvc中导出Excel表格中的表视图

EN

public ActionResult Show(int id)
    {
        IEnumerable<GradeSheetViewModel> model = _repGrade.GetList(id);
        return View(model);
    }

public ActionResult ExportToExcel()
    {
        var gv = new GridView();
        gv.DataSource = this.Show();
        gv.DataBind();
        Response.ClearContent();
        Response.Buffer = true;
        Response.AddHeader("content-disposition", "attachment; filename=DemoExcel.xls");
        Response.ContentType = "application/ms-excel";
        Response.Charset = "";
        StringWriter objStringWriter = new StringWriter();
        HtmlTextWriter objHtmlTextWriter = new HtmlTextWriter(objStringWriter);
        gv.RenderControl(objHtmlTextWriter);
        Response.Output.Write(objStringWriter.ToString());
        Response.Flush();
        Response.End();
        return View("Index");
    } 

gv.DataSource = this.Show();