Save excel file from GridView to local computer ASP.NET VB

Response.Clear()
			Response.Buffer = True
			Response.AddHeader("content-disposition", "attachment;  filename=test.xls")
			Response.ContentEncoding = System.Text.Encoding.default
			Response.Charset = ""
			Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
			dim sWriter As New StringWriter()
			Dim hWriter As New HtmlTextWriter(sWriter)
			GridView1.AllowPaging = False
GridView1.RenderControl(hWriter)
			Response.Output.Write(sWriter.ToString())
			Response.Flush()
			Response.End()