Write gridview to excel page

Question

I'm getting the following error

Error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not 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.

I want to put the grid in excel onclick

Sub bttntxtfile_Click(ByVal sender As Object, ByVal e As EventArgs)
    GridViewExportUtil.Export("Customers.xls", GridView1)
End Sub

public class GridViewExportUtil
{

public static void Export(string fileName, GridView gv)
{
    HttpContext.Current.Response.Clear();
    HttpContext.Current.Response.AddHeader(
        "content-disposition", string.Format("attachment; filename={0}", fileName));
    HttpContext.Current.Response.ContentType = "application/ms-excel";

    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter htw = new HtmlTextWriter(sw))
        {
            //  Create a form to contain the grid
            Table table = new Table();

            //  add the header row to the table
            if (gv.HeaderRow != null)
            {
                GridViewExportUtil.PrepareControlForExport(gv.HeaderRow);
                table.Rows.Add(gv.HeaderRow);
            }

            //  add each of the data rows to the table
            foreach (GridViewRow row in gv.Rows)
            {
                GridViewExportUtil.PrepareControlForExport(row);
                table.Rows.Add(row);
            }

            //  add the footer row to the table
            if (gv.FooterRow != null)
            {
                GridViewExportUtil.PrepareControlForExport(gv.FooterRow);
                table.Rows.Add(gv.FooterRow);
            }

            //  render the table into the htmlwriter
            table.RenderControl(htw);

            //  render the htmlwriter into the response
           HttpContext.Current.Response.Write(sw.ToString());

        }
    }
}

/// <summary>
/// Replace any of the contained controls with literals
/// </summary>
/// <param name="control"></param>
private static void PrepareControlForExport(Control control)
{
    for (int i = 0; i < control.Controls.Count; i++)
    {
        Control current = control.Controls[i];
        if (current is LinkButton)
        {
            control.Controls.Remove(current);
            control.Controls.AddAt(i, new LiteralControl((current as LinkButton).Text));
        }
        else if (current is ImageButton)
        {
            control.Controls.Remove(current);
            control.Controls.AddAt(i, new LiteralControl((current as ImageButton).AlternateText));
        }
        else if (current is HyperLink)
        {
            control.Controls.Remove(current);
            control.Controls.AddAt(i, new LiteralControl((current as HyperLink).Text));
        }
        else if (current is DropDownList)
        {
            control.Controls.Remove(current);
            control.Controls.AddAt(i, new LiteralControl((current as DropDownList).SelectedItem.Text));
        }
        else if (current is CheckBox)
        {
            control.Controls.Remove(current);
            control.Controls.AddAt(i, new LiteralControl((current as CheckBox).Checked ? "True" : "False"));
        }

        if (current.HasControls())
        {
            GridViewExportUtil.PrepareControlForExport(current);
        }
    }
}
}

I have two response.redirects but i commented them out and I still got the error. Has anyone ever seen this error before? Am I doing something wrong?

I think it has something to do with the httpcontext.current.response.clear and httpContext.current.response.addheader lines

Answer 1

The 'PageRequestManagerParserErrorException' may be caused by the call to Response.Write() if your 'Export to Excel' button is located inside of an update panel. Either remove the button from within the update panel or use a PostBackTrigger.

See this article for more information.