Question

I have a windows service and I’m injecting a module to it:

private ICoupon _couponManager;
...
DirectoryCatalog catalog = new DirectoryCatalog(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Plugins"));
_container = new CompositionContainer(catalog);
_couponManager = _container.GetExportedValue<ICoupon>();// Here I'm getting an exception

But the module that I’m trying to import is an constructer injected module:

[Import(typeof(IWallet))]
private IWallet _iWallet;

private static CompositionContainer _container;

public CouponManager()
{
    DirectoryCatalog catalog = new DirectoryCatalog(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Plugins"));
    _container = new CompositionContainer(catalog);
    _container.ComposeParts();
}

So I’m getting “An exception occurred while trying to create an instance of type ‘X.Business.CouponManager’.” error. How do I have to inject my module?

I’m not sure if my question is clear, if not please ask for details.

Thanks in advance,

Edit: The interesting part is: I can inject this module to my asp.net mvc application and use it without problem.

Answer 1

in addition to Gilles answer your class should look like this

[Export(typeof(ICoupon))]
public class CouponManager : ICoupon 
{
  private IWallet _iWallet;

  [ImportingConstructor]
  public CouponManager(IWallet iwallet)
  {
     this._iWallet= iwallet;
  }
}