Using Entity Framework with repository pattern in WinForms MDI

Question

Hi,

We are about to start up a new project similar to a previous one. I could just copy the old design but I am not all too satisified with the old design.

It is a "standard" business system (sales,stocktaking,warehousing etc) built ontop of .Net 3.5 (Winforms MDI) with Entity Framework in the backend.

All forms inherit from a baseform (which inherits Windows.Form). The form exposes a property called ObjectContext, which on the first call instantiates a new ObjectContext. This makes up a pretty good UnitOfWork i think, having all data-access isolated in each form.

However.

I have encapsulated all queries and common CRUD in "poor mans repositories". These Repositories are exposed as properties of the ObjectContext.

So if I wanted to bind and order to a form I would call OrderLinesGrid = ObjectContext.OrderRepository.GetOrderLinesByID(orderID).

The OrderRepository gets a reference to the objectcontext created for the form, like this

(In my partial ObjectContext class)

Private _OrderRepository as OrderRepository
Public ReadOnly Property OrderRepository as OrderRepository
Get
if _orderrepository is nothing then
_orderrepository = New OrderRepository(me)
end if
return _orderrepository
End Get
End Property

What I do not like about this is:

1. The call to the repository is made through ObjectContext. Hence, I do not get abstraction between the query and the dataaccesslayer I would like.

2. For each new type in my Domain I need to create a property in my ObjectContext

My call to OrderRepository should just return domain objects and not worry about how it is persisted. Also, I cannot have each Repository have it's own ObjectContext since that would require me to Attach and Detach objects when referencing i.e Country to a Order.Country property.

I would appreciate any ideas and feedback on this design :)