Control 'grid 1' of type 'GridView' must be placed inside a form tag with runat=server.

Because calling GridView.RenderControl(htmlTextWriter)raises 

an exception that aserver control was rendered outside of a form.

We can avoid this exception byoverriding VerifyRenderingInServerForm

public override void VerifyRenderingInServerForm(Control control)
{
  /* Confirms that an HtmlForm control is rendered

     for the specified ASP.NET
     server control at run time. */
} 

*Note that there is nothing inside the function.