Autofac: Missing Method Involving MvvmLight RelayCommand - wpf

Question

I have a generic collection class based on the MvvM Light library which I've registered with Autofac:
public class DialogCollection<TViewModel> : ObservableCollection<TViewModel>, IDialogCollection<TViewModel>
{
private readonly IUIManager _uiManager;
public DialogCollection( IUIManager uiManager )
{
_uiManager = uiManager ?? throw new NullReferenceException( nameof(uiManager) );
ViewModelSelectedCommand = new RelayCommand<TViewModel>( DetailItemSelectedHandler );
AddNewViewModelCommand = new RelayCommand( AddNewItemHandler );
}
public RelayCommand<TViewModel> ViewModelSelectedCommand { get; }
public RelayCommand AddNewViewModelCommand { get; }
}
Autofac registration:
builder.RegisterGeneric( typeof(DialogCollection<>) )
.As( typeof(IDialogCollection<>) );
IUIManager, the only argument to the DialogCollection constructor, is also registered with Autofac, and is properly instantiated when the program runs.
The specific instance of IDialogCollection is generated from a lambda method created by Autofac, which is passed in thru the constructor of a class which holds an instance of the collection I want to create:
public class CommunitiesModel
{
private readonly Func<IDialogCollection<CommunityModel>> _colBuilder;
private readonly Func<CommunityModel> _communityBuilder;
private DialogCollection<CommunityModel> _communities;
public CommunitiesModel(
Func<IDialogCollection<CommunityModel>> colBuilder,
Func<CommunityModel> commmunityBuilder
)
{
_colBuilder = colBuilder ?? throw new NullReferenceException(nameof(colBuilder));
_communityBuilder= commmunityBuilder?? throw new NullReferenceException(nameof(commmunityBuilder));
}
// I'm not showing how Load() gets called, but it does :)
public override void Load()
{
// this next line creates an instance of DialogCollection
// it's also where the Autofac Missing Method exception gets thrown
Communities = (DialogCollection<CommunityModel>) _colBuilder();
}
}
Both colBuilder and communityBuilder are properly instantiated when passed into the CommunitiesModel constructor, which I presume means Autofac was able to use the registration information to create methods that create instances of those classes.
I don't understand why there's a missing method exception when _colBuilder() is executed, since the code compiles fine (meaning the RelayCommand ctor is known and available).
If I comment out the two RelayCommand creation lines (i.e., "new RelayCommand...") in the definition of DialogCollection<>, the exception is not thrown.
Which means the Autofac creator method is gacking on not finding something inside a constructor which has already been called with the appropriate constructur arguments.
Here is the exception that gets thrown:
Autofac.Core.DependencyResolutionException HResult=0x80131500
Message=An error occurred during the activation of a particular
registration. See the inner exception for details. Registration:
Activator = DialogCollection1 (ReflectionActivator),
Services =[WpfFramework.IDialogCollection1[[Olbert.CommunityScanner.Manager.ViewModel.CommunityModel,
CommunityScannerManager, Version=0.0.0.1, Culture=neutral,
PublicKeyToken=null]]], Lifetime =
Autofac.Core.Lifetime.CurrentScopeLifetime, Sharing = None, Ownership
= OwnedByLifetimeScope Source=Autofac StackTrace: at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable1
parameters) at Autofac.Core.Resolving.InstanceLookup.Execute()
at
Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope
currentOperationScope, IComponentRegistration registration,
IEnumerable1 parameters) at
Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration
registration, IEnumerable1 parameters) at
Autofac.Core.Lifetime.LifetimeScope.ResolveComponent(IComponentRegistration
registration, IEnumerable1 parameters) at
Olbert.CommunityScanner.Manager.ViewModel.CommunitiesModel.Load() in
C:\Programming\CommunityScanner\CommunityScannerManager\ViewModel\CommunitiesModel.cs:line
58 at
Olbert.CommunityScanner.Manager.ViewModel.AppStateModel.set_ActivePageInfo(PageInfo
value) in
C:\Programming\CommunityScanner\CommunityScannerManager\ViewModel\AppWide\AppStateModel.cs:line
117 at
Olbert.CommunityScanner.Manager.App.OnStartup(StartupEventArgs e) in
C:\Programming\CommunityScanner\CommunityScannerManager\App.xaml.cs:line
44 at System.Windows.Application.<.ctor>b__1_0(Object unused) at
System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate
callback, Object args, Int32 numArgs) at
System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source,
Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl() at
System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object
state) at
MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object
obj) at
System.Threading.ExecutionContext.RunInternal(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) in
f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 954
at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) in
f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 901
at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state) in
f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs:line 890
at
MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext
executionContext, ContextCallback callback, Object state) at
System.Windows.Threading.DispatcherOperation.Invoke() at
System.Windows.Threading.Dispatcher.ProcessQueue() at
System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32
msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at
MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam,
IntPtr lParam, Boolean& handled) at
MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at
System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate
callback, Object args, Int32 numArgs) at
System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source,
Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at
System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority
priority, TimeSpan timeout, Delegate method, Object args, Int32
numArgs) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd,
Int32 msg, IntPtr wParam, IntPtr lParam) at
MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at
System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame
frame) at
System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Application.RunDispatcher(Object ignore) at
System.Windows.Application.RunInternal(Window window) at
System.Windows.Application.Run(Window window) at
System.Windows.Application.Run() at
Olbert.CommunityScanner.Manager.App.Main()
Inner Exception 1: DependencyResolutionException: An exception was
thrown while invoking the constructor 'Void
.ctor(WpfFramework.IUIManager)' on type 'DialogCollection`1'.
Inner Exception 2: MissingMethodException: Method not found: 'Void
GalaSoft.MvvmLight.Command.RelayCommand1..ctor(System.Action1)'.
I can provide more details if needed; what I've shown here is abstracted from a larger code base, but hopefully shows the relevant details.

Answer 1

I would recommend looking at RelayCommand1 - it appears IUIManager or DialogCollection<T> needs that constructor and it's not there. Work bottom up on this. The Autofac part is red herring. Meat of the issue is the inner exception at the bottom.