Question

I’m trying to invoke the RegisterType method in the Unity container. RegisterType has a total of 16 overrides (some of those are parameters some are types).

I’m trying to perform the equivalent of:

Container.RegisterType<IMyDataProvider, MockData.MockProvider>("MockData", new ContainerControlledLifetimeManager())

Using GetMethod() was a total failure, so I ended up doing this ugly thing:

     MethodInfo registerTypeGeneric = Container.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance).
        Where(p => p.ToString() == "Microsoft.Practices.Unity.IUnityContainer RegisterType[TFrom,TTo](System.String, Microsoft.Practices.Unity.LifetimeManager, Microsoft.Practices.Unity.InjectionMember[])").FirstOrDefault();
     MethodInfo registerTypeSpecific = registerTypeGeneric.MakeGenericMethod( new Type[] { typeof(IMyDataProvider), Assembly.LoadFrom("MockData.dll").GetType("MockData.MockProvider") });
     registerTypeSpecific.Invoke(Container, new object[] { "MockData", new ContainerControlledLifetimeManager() });

And this works beautifully, up until the Invoke which complains because I have no InjectionMember parameters (they’re optional and I don’t have any to give). So, according to the documentation, I have to use Type.InvokeMember() to call a method with optional parameters.

So I did this:

     Binder binder = new BootstrapperBinder();
     Container.GetType().InvokeMember("RegisterType",
        BindingFlags.Instance | BindingFlags.Public | BindingFlags.OptionalParamBinding | BindingFlags.InvokeMethod,
        binder,
        Container,
        new object[] { "MockData", new ContainerControlledLifetimeManager() });

My BoostrapperBinder class does this:

  public override MethodBase BindToMethod(BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, System.Globalization.CultureInfo culture, string[] names, out object state)
  {
     Type mockProvider = Assembly.LoadFrom("MockData.dll").GetType("MockData.MockProvider");
     state = new object();
     MethodInfo mi = Container.GetType().GetMethods(BindingFlags.Public | BindingFlags.Instance).
        Where(p => p.ToString() == "Microsoft.Practices.Unity.IUnityContainer RegisterType[TFrom,TTo](System.String, Microsoft.Practices.Unity.LifetimeManager, Microsoft.Practices.Unity.InjectionMember[])").FirstOrDefault();
     return mi.MakeGenericMethod(new Type[] { typeof(ICarrierApprovalDataChangeAccessorEndPoint), mockProvider });
  }

Yes, it’s ugly, but I just use it for this oen case, so it does the job.

Now, the problem is, it’s still complaining about the lack of a third parameter. I can’t pass null or Missing.Value either, or it croaks. I’ve tried with and without BindingFlags.OptionalParamBinding. I’m stumped.

(Edited to put the Container.RegisterType example in code)

Answer 1

My initial post mentioned that I had tried passing null as a 3rd parameter and that the app “croaked.” Specifically, it was getting a null reference exception and I should have been more clear about that.

The solution was to pass “new InjectionMember[0]” instead of null, so the Invoke() should have looked like this:

registerTypeSpecific.Invoke(Container, new object[] { "MockData", new ContainerControlledLifetimeManager(), new InjectionMember[0] }); 

Thanks to Jason for his help. His sample sent me down the path that eventually led to the answer.