Issues exporting datagridview to excel

Question

Hi all- I'm trying to do an export of a datagrid to excel. For some reason, known working methods aren't working. The export is done from a user control. My page (default.aspx) uses a master page and the page has a user control that actually has the datagrid I'm trying to export.

Here's my code on the ascx:

Response.ClearContent();
 Response.AddHeader("content-disposition", "attachment; filename=MyExcelFile.xls");
Response.ContentType = "application/excel";
 StringWriter sw = new StringWriter();
 HtmlTextWriter htw = new HtmlTextWriter(sw);
_gvwResults.RenderControl(htw);
Response.Write(sw.ToString());
Response.End();

On my default.aspx (page the holds the ascx) is this code:

public override void VerifyRenderingInServerForm(Control control)
{
    /* Confirms that an HtmlForm control is rendered for the specified ASP.NET
       server control at run time. - required to export file */
}

Here's the error I receive: Sys.Webforms.pagerequestmanagerparsererrorexception. The message received from the server could ot be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, httpmodules or server trace is enabled.

Any ideas? This code should work but it's almost as if the response object is not being cleared. Ideas?

Answer 1

Turns out that the since the combobox was ajaxified, the export was not happening. The event was firing but, as the error message says, it was response.writing onto the existing page, thus throwing the error, which would not allow for a new document (xls in this case) to be rendered. After setting the combobox to do a postback on the page and un-ajaxifying it, the export started working..