The control "XXXX" of type "XXX" must be placed inside the form tag with Runat=server.

issue: The control "XXXX" of type "GRID1" must be placed inside the form tag with Runat=server.
Note: GRID1 is the ID of the table.

Find the solution on the internet roughly as follows:
1) Put the grid on the <form
runat= "Server" ></form> room.
2) tag the grid with runat= "Server".

Find out that the foreground grid does have markup runat= "Server", and the table is placed in the form.
Workaround: Add the following override method in the background code
public override void
Verifyrenderinginserverform (Control Control)
{ }

Find the MSDN description, which is intended to verify that the Form control is rendered for the specified ASP. NET mobile control at run time.

SOURCE Quote: Http://www.jb51.net/article/21635.htm