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c#wpfc#-4.0mvvmmef

Create instance from attribute

I'm using MVVM viewmodel-first pattern in a WPF application and I have some definitions like these:

public interface IMyView { }

[Export(typeof(IMyView))]
public class MyView : UserControl, IMyView { }

[ViewTypeAttribute(typeof(IMyView))]
public interface IMyViewModel { }

[Export(typeof(IMyViewModel))]
public class MyViewModel : ViewModelBase, IMyViewModel { }

That the ViewTypeAttribute is a custom attribute to retrive which View should be used as DataTemplate for the given ViewModel. Really here I have a Type! But I don't know how to create an instance from that Type via MEF? can anybody help me please?

Solution

  • use:

    var container = new CompositionContainer(/* your container .ctor here */);
var type = typeof (IYourType); // read the type from attribute
var export = container.GetExports(type, null, null).FirstOrDefault();
var obj = export.Value as YourCostingHere;