Question

I have a default Entity Framework model that holds all of my default tables for my product, and that all customers share in common. However, on some customers, I have some custom tables that exist for only that customer, but they relate to the default product’s tables. I have a second Entity Framework model to hold these custom tables.
My question is how can I make a Linq to Entities query using Join so I can relate the entities from my default model to the tables on my custom model? I don’t mind not having the Navigation properties from the custom entity to the entities on the default model; I just need a way to query both models in a single query.
Below is the code:

  using (ProductEntities oProductDB = new ProductEntities())
  {
    using (ProductEntitiesCustom oProductCustomDB = new ProductEntitiesCustom())
    {
      var oConsulta = oProductCustomDB.CTBLCustoms
                .Where(CTBLCustoms => CTBLCustoms.IDWOHD >= 12)
                .Join(oProductDB.TBLResources,
                     CTBLCustoms => new
                       {
                         CTBLCustoms.IDResource
                       },
                     TBLResources => new
                       {
                         TBLResources.IDResource
                       },
                    (CTBLCustoms, TBLResources) => new
                       {
                         IDCustom = CTBLCustoms.IDCustom,
                         Descricao = CTBLCustoms.Descricao,
                         IDWOHD = CTBLCustoms.IDWOHD,
                         IDResource = CTBLCustoms.IDResource,
                         ResourceCode = TBLResources.Code
                       });

      gvwDados.DataSource = oConsulta;
    }
  }

I get a The specified LINQ expression contains references to queries that are associated with different contexts error.
EDIT
Could I merge the 2 ObjectContext into a third, and then run the Linq query?
Tks

EDIT

Below is the code that worked, using the AsEnumerable() proposed solution:

  using (ProductEntities oProductDB = new ProductEntities())
  {
    using (ProductEntitiesCustom oProductCustomDB = new ProductEntitiesCustom())
    {
      var oConsulta = (oProductCustomDB.CTBLCustoms.AsEnumerable()
                .Where(CTBLCustoms => CTBLCustoms.IDWOHD >= 12)
                .Join(oProductDB.TBLResources,
                     CTBLCustoms => new
                       {
                         CTBLCustoms.IDResource
                       },
                     TBLResources => new
                       {
                         TBLResources.IDResource
                       },
                    (CTBLCustoms, TBLResources) => new
                       {
                         IDCustom = CTBLCustoms.IDCustom,
                         Descricao = CTBLCustoms.Descricao,
                         IDWOHD = CTBLCustoms.IDWOHD,
                         IDResource = CTBLCustoms.IDResource,
                         ResourceCode = TBLResources.Code
                       })).ToList();

      gvwDados.DataSource = oConsulta;
    }
  }

I added the AsEnumerable() as suggested, but I had to add the ToList() at the end so I could databind it to the DataGridView.

Answer 1

You can’t do this in L2E. You could bring this into object space with AsEnumerable(), and it would work, but possibly be inefficient.

Merging the ObjectContexts is possible, and would work, but would need to be done manually.