Connect to an Entity Model using Reflection

Question

I'm writing a little utility to load Entity Data Models from an assembly and query against them.

I've tried using Reflection to load a derived ObjectContext, but ObjectContext doesn't derive from MarshalByRefObject so I can't pass parameters to the constructor with Activator.CreateInstance() (according to the exception I get.)

Is it possible to load an Entity Model defined and stored in an external assembly using Reflection, "late bind" to the EDM, and perform queries against it if you provide a valid connection string?

Answer 1

The EDM Model that derives from the ObjectContext has the ConnectionString name which it passes to the base constructor from it's own default constructor. Like below.

    public const string ConnectionString = "name=My_Entities";
    public const string ContainerName = "My_Entities";

    #region Constructors

    public My_Entities()
        : base(ConnectionString, ContainerName)
    {
        Initialize();
    }

    #endregion

You can always change the Connection details via the ObjectContext.Connection.

Answer 2

I believe ObjectContext.Metadataworkspace.LoadFromAssembly() is what your looking for:

http://msdn.microsoft.com/en-us/library/bb495513.aspx