problem when exporting gridview content into excel

Question

I have a Master page and a child page in child page i have  a gridview showing the record set i want to export and print this records so i am using that code on button click event ...

Response.Clear()

Response.Buffer = True

Response.AddHeader("content-disposition",

"attachment;filename=GridViewExport.doc")

Response.Charset = ""

Response.ContentType = "application/vnd.ms-word "

Dim sw As New StringWriter()

Dim hw As New HtmlTextWriter(sw)

grdUserReports.AllowPaging = False

grdUserReports.DataBind()

grdUserReports.RenderControl(hw)

Response.Output.Write(sw.ToString())

Response.Flush()

Response.End()

 

The highlited row gives error that

"Control 'ctl00_ContentPlaceHolder1_grdUserReports' of type 'GridView' must be placed inside a form tag with runat=server."