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I am using WPF with Entity Framework 6 (DB first), Caliburn.Micro, and MEF.

I am trying to implement IoC in my project. I am an absolute beginner in IoC, and unfortunately, I cant find too many examples where MEF is used with Repository Pattern.

So I have a few repositories, and I have created my Generic Unit of Work like this:

class GenericUoW : IUoW, IDisposable
    protected readonly DbContext _ctx;

    public GenericUoW(DbContext context)
        _ctx = context;

    public void Complete()

    public void Dispose()

My actual Unit of Work classes are implemented like this:

class InvoiceUoW : GenericUoW, IInvoiceUoW
    public InvoiceUoW(DbContext _ctx) : base(_ctx)
        salesrepo = new SaleRepository(_ctx);
        itemsrepo = new ItemRepository(_ctx);
        materialrepo = new MaterialRepository(_ctx);
        raterepo = new RateRepository(_ctx);
        clientrepo = new ClientRepository(_ctx);
        taxrepo = new TaxRepository(_ctx);
        stockhistoryrepo = new StockHistoryRepository(_ctx);
        proformarepo = new ProformaRepository(_ctx);

    public ISaleRepository salesrepo { get; private set; }
    public IItemRepository itemsrepo { get; private set; }
    public IMaterialRepository materialrepo { get; private set; }
    public IRateRepository raterepo { get; private set; }
    public IClientRepository clientrepo { get; private set; }
    public ITaxRepository taxrepo { get; private set; }
    public IStockHistoryRepository stockhistoryrepo { get; private set; }
    public IProformaRepository proformarepo { get; private set; }

Now, in my ViewModel, I am doing something like this:

class InvoiceViewModel : PropertyChangedBase

    #region ctor
    public InvoiceViewModel(IInvoiceUoW invoiceUoW)
        _uow = invoiceUoW;
        Clients = new BindableCollection<Client>(_uow.clientrepo.FetchAll());


    private readonly IInvoiceUoW _uow;

    //other properties and methods

My question is related to the use of IoC/DI in InvoiceUoW. How do I implement constructor injection in that class? Because each of those repositories in that class has to be instantiated with the same DataContext. Please do note that I have several Unit of Work classes, each for one viewmodel.

What I have tried:

When I try to do this with MEF, by making the constructor of InvoiceUoW something like this

public InvoiceUoW(DbContext _ctx, ISaleRepository salerepo, IItemRepository itemsrepo,IMaterialRepository materialrepo, ... ) : base(_ctx)

it does something equivalent to this:

salesrepo = new SaleRepository(new DbContext()); 
itemsrepo = new ItemRepository(new DbContext()); 
materialrepo = new MaterialRepository(new DbContext());

How can I instantiate all repositories using the same DbContext? I have thought of using a factory, but that will unnecessarily complicate the code.
Tomas Takac 29-Mar-17 2:46am    
Why do you need the repositories to be injected? What is the benefit? Maybe you are taking this too far. Just a thought.
Sabyasachi Mukherjee 2-May-17 8:09am    
So, I should just inject the DbContext?
Tomas Takac 2-May-17 9:10am    
I'm saying your code is just fine as it is now, do not complicate it unnecessarily.

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