ViewModelBinder.cs

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using System;
using System.Windows;
using Dreamine.MVVM.Locators;
 
namespace Dreamine.MVVM.Locators.Wpf
{
    public static class ViewModelBinder
    {
        public static readonly DependencyProperty AutoWireViewModelProperty =
            DependencyProperty.RegisterAttached(
                "AutoWireViewModel",
                typeof(bool),
                typeof(ViewModelBinder),
                new PropertyMetadata(false, OnAutoWireViewModelChanged));

        public static bool GetAutoWireViewModel(DependencyObject obj)
        {
            return (bool)obj.GetValue(AutoWireViewModelProperty);
        }

        public static void SetAutoWireViewModel(DependencyObject obj, bool value)
        {
            obj.SetValue(AutoWireViewModelProperty, value);
        }

        public static FrameworkElement ResolveView(object viewModel)
        {
            if (viewModel is null)
            {
                throw new ArgumentNullException(nameof(viewModel));
            }
 
            Type viewModelType = viewModel.GetType();
            string fullName = viewModelType.FullName
                ?? throw new InvalidOperationException($"Cannot determine the full type name for {viewModelType.Name}.");
 
            string[] candidates = ViewNamingConvention.GetViewTypeNameCandidates(fullName);
            Type? viewType = FindViewType(candidates);
 
            if (viewType is null)
            {
                throw new InvalidOperationException($"Cannot find a View for candidates: {string.Join(" or ", candidates)}.");
            }
 
            FrameworkElement view = (FrameworkElement)Activator.CreateInstance(viewType)!;
            view.DataContext = viewModel;
 
            return view;
        }

        private static void OnAutoWireViewModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is FrameworkElement view && e.NewValue is true)
            {
                object? viewModel = ViewModelLocator.Resolve(view.GetType());
                if (viewModel is not null)
                {
                    view.DataContext = viewModel;
                }
            }
        }

        private static Type? FindViewType(string[] candidateTypeNames)
        {
            foreach (string candidateTypeName in candidateTypeNames)
            {
                foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
                {
                    Type? viewType = assembly.GetType(candidateTypeName);
                    if (viewType is null)
                    {
                        continue;
                    }
 
                    if (!typeof(FrameworkElement).IsAssignableFrom(viewType))
                    {
                        continue;
                    }
 
                    if (viewType.IsAbstract)
                    {
                        continue;
                    }
 
                    return viewType;
                }
            }
 
            return null;
        }
    }
}