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entity framework 4.1 - Convert DBContext to ObjectContext for use with GridView

I have a webforms project using EF codefirst to persist data. I'd like to use a GridView and EntityDataSource, in order to save writing CRUD. Is this possible?

Can I convert my DBContext to an ObjectContext that is expected by the EntityDataSource?

Here's what I tried:

<asp:EntityDataSource ID="OrdersDataSource" runat="server" ContextTypeName="SomeNamespace.Models.ShopDBContext" 
     EnableFlattening="False" EntitySetName="Orders" EntityTypeFilter="Order" EnableDelete="False" 
     EnableUpdate="False" Include="OrderLines" OrderBy="it.Id"> 
</asp:EntityDataSource>

<asp:GridView ID="OrdersGridView" runat="server" AllowPaging="True" AllowSorting="True" 
     AutoGenerateColumns="True" DataKeyNames="Id" DataSourceID="OrdersDataSource" /> 

However I get this exception:

Unable to cast object of type 'SomeNamespace.Models.ShopDBContext' to type 'System.Data.Objects.ObjectContext'.

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Try this:

var context = new YourDbContext();
var adapter = (IObjectContextAdapter)context;
var objectContext = adapter.ObjectContext;

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