[BUG] RegisterViewsForViewModels throws System.InvalidOperationException: "Sequence contains no matching element"

[mmuecke]

Describe the bug
Locator.CurrentMutable.RegisterViewsForViewModels(AssemblyType); throws this excpetion

System.InvalidOperationException
HResult=0x80131509
Nachricht = Sequence contains no matching element
Quelle = System.Linq
Stapelüberwachung:
at System.Linq.ThrowHelper.ThrowNoMatchException()
at System.Linq.Enumerable.First[TSource](IEnumerable1 source, Func2 predicate)
at ReactiveUI.DependencyResolverMixins.TypeFactory(TypeInfo typeInfo) in d:\a\1\s\src\ReactiveUI\Mixins\DependencyResolverMixins.cs:line 109
at ReactiveUI.DependencyResolverMixins.RegisterViewsForViewModels(IMutableDependencyResolver resolver, Assembly assembly) in d:\a\1\s\src\ReactiveUI\Mixins\DependencyResolverMixins.cs:line 88
at MyApp.App.d__1.MoveNext() in C:\xyz

Steps To Reproduce

• I don't know how to reproduce the exception. I will give more information if I find the code braking it. I just made some minor changes in the code. Even not adding IViewFor<> or so.
• I tryed another assembly with no view models, there no exception in thrown.
• The code already run successful

Expected behavior

• Cache the exception and go on normal
• Throw a more meaningful exception

Code
Here is the line of code:

ReactiveUI/src/ReactiveUI/Mixins/DependencyResolverMixins.cs

Line 109 in 371b7fc

return Expression.Lambda<Func<object>>(Expression.New(

Environment

• OS: Win 10 VS 2019 V16.6.0
• Version .net core 3.1, ReactiveUI WPF 11.4.1

[mmuecke]

I found the problem. I had registered a IViewFor<AppViewModel> for the main window and the main Window hat no parameter less constructor. To throw a more meaningful exception here would be great. The exception should show to the problem and the causing class.

public partial class MainWindow : MetroWindow, IViewFor<AppViewModel>
{
	public static readonly DependencyProperty ViewModelProperty = DependencyProperty.Register(
		"ViewModel", typeof(AppViewModel), typeof(MainWindow), new PropertyMetadata(default(AppViewModel)));

	// public MainWindow()
	// {
	// }
		
	public MainWindow(AppViewModel appViewModel)
	{
            InitializeComponent();
            ViewModel = appViewModel;
	}

        object IViewFor.ViewModel
        {
            get { return ViewModel; }
            set { ViewModel = (AppViewModel)value; }
        }

        public AppViewModel ViewModel
        {
            get { return (AppViewModel)GetValue(ViewModelProperty); }
            set { SetValue(ViewModelProperty, value); }
        }
    }

}

[glennawatson]

Feel free to submit a pr. If you want help with how to do that let me know

[github-actions]

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