Download datatable as excel 2013 file

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C#

ASP.NET

MVC

MS-Excel

Dears,

I want to download a DataTable Data as Excel 2013 File Not excel 2003.
Here is my code:

private void DownloadExcelReport(DataTable dtResult)
        {
            var gv = new GridView
            {
                DataSource = dtResult
            };
            gv.DataBind();
            Response.ClearContent();
            Response.Buffer = true;
            Response.AddHeader("content-disposition", "attachment; filename=AllDataReport.xlsx");
            Response.ContentType = "application/application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
            Response.Write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />");            
            StringWriter objStringWriter = new StringWriter();
            HtmlTextWriter objHtmlTextWriter = new HtmlTextWriter(objStringWriter);
            gv.RenderControl(objHtmlTextWriter);
            Response.Output.Write(objStringWriter.ToString());
            Response.End();
        }

The Result:
The file is downloaded as .xlsx File but i CANNOT OPEN IT.
This Message Appears:
Excel cannot open the file because the extension is not valid verify that the file is not corrupted and that the file extension matches the format of the file.

What I have tried:

I did some search and i found the following:
Change the content type and response header from this:
//Response.AddHeader("content-disposition", "attachment; filename=AllDataReport.xls");
//Response.ContentType = "application/ms-excel";

To Be Like This:
Response.AddHeader("content-disposition", "attachment; filename=AllDataReport.xlsx");
Response.ContentType = "application/application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";