Question

I have a custom type instance that needs to be registered in code:

container.RegisterType( typeof(Isome), myvar);

so it can be used normally like this:

 [Import] 
 ISome var1 ;

How do I get a reference to the container?

Answer 1

I don’t know about Prism, but in MEF you don’t register types with the container – that introduces a dependency that defeats the purpose of decoupling the code.

What you do to make the ISome type available for MEF to discover is you put an [Export(typeof(ISome))] attribute on your class that implements the ISome interface.

In composition, MEF will see the Import attribute keyed on the ISome interface type, then go looking for a matching Export keyed on the ISome interface type. It will find your implementation class with the Export attribute. MEF will create an instance of the exported class and assign it to the import property for you.

In the composition step, you need to provide a catalog of types or assemblies for MEF to load and do its matchmaking magic. Make sure the assembly that contains your implementation class is in that catalog group.