Hi, Imar
Finally, I get the reason why my site gets the error.
I replace this piece of code
Code:
ImageUrl: <asp:Label ID="ImageUrl"
runat="server"
Text='<%# Eval("ImageUrl") %>' /><br />
with
Code:
ImageUrl: <asp:Image ID="ImageUrl" runat="server"
Text='<%# Item("ImageUrl") %>' /><br />
by mistake in "ManagePhotoAlbum.aspx".
So that causes the error.
Thank you for the help!