DropDownList binding get Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control exception

I'm going mad for this problem... I've an user control that has a FormView for the insert operations and a GridView for all others.
In both controls I've a DropDownList as follow:
<asp:DropDownList ID="DropDownList" runat="server" DataSourceID="ObjectDataSource" DataTextField="Text" SelectedValue='<%# Bind("Code") %>' DataValueField="Code" AppendDataBoundItems="True" Width="200px" /> The error in the subject comes if the DropDownList in the FormView is present, if I comment it the DropDownList in the GridView works perfectly! It binds in edit mode and updates the value with out any problem!
But they are the same and only the ID changes.
The funny thing is that I've also another page with the same controls it works...
Does someone has any idea?
Thank you
Some more details:
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