rewrite ObservableCollectionViewModel

Hyperbar.Windows/App.xaml.cs

@@ -52,13 +52,16 @@ public partial class App :
                 {
                     static IEnumerable<WidgetContainerViewModel> Resolve(IServiceProvider services)
                     {
+                        int index = 0;
                         foreach (IWidgetContext widgetContext in services.GetServices<IWidgetContext>())
                         {
                             if (widgetContext.ServiceProvider.GetServices<IWidgetViewModel>() is
                                 IEnumerable<IWidgetViewModel> viewModels)
                             {
                                 yield return (WidgetContainerViewModel)ActivatorUtilities.CreateInstance(widgetContext.ServiceProvider,
-                                    typeof(WidgetContainerViewModel), viewModels);
+                                    typeof(WidgetContainerViewModel), viewModels, index % 2 == 0);
+
+                                index++;
                             }
                         }
                     }

Hyperbar.Windows/Views/WidgetContainerView.xaml

@@ -4,11 +4,24 @@
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:ui="using:Hyperbar.Windows.UI">
-    <ItemsControl ItemTemplateSelector="{Binding Converter={ui:DataTemplateConverter}}" ItemsSource="{Binding}">
-        <ItemsControl.ItemsPanel>
-            <ItemsPanelTemplate>
-                <StackPanel Orientation="Horizontal" />
-            </ItemsPanelTemplate>
-        </ItemsControl.ItemsPanel>
-    </ItemsControl>
+    <Grid>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="Auto" />
+            <ColumnDefinition Width="*" />
+        </Grid.ColumnDefinitions>
+        <Rectangle
+            Width="1"
+            Margin="6,0,6,0"
+            Fill="Red" />
+        <ItemsControl
+            Grid.Column="1"
+            ItemTemplateSelector="{Binding Converter={ui:DataTemplateConverter}}"
+            ItemsSource="{Binding}">
+            <ItemsControl.ItemsPanel>
+                <ItemsPanelTemplate>
+                    <StackPanel Orientation="Horizontal" />
+                </ItemsPanelTemplate>
+            </ItemsControl.ItemsPanel>
+        </ItemsControl>
+    </Grid>
 </UserControl>

Hyperbar/Views/ObservableCollectionViewModel.cs

@@ -1,22 +1,31 @@
-using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using System.Collections;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
 
 namespace Hyperbar;
 
-
-public class ObservableCollectionViewModel<TItem> :
-    ObservableCollection<TItem>,
+public partial class ObservableCollectionViewModel<TItem> : 
+    ObservableObject,
+    IList<TItem>, 
+    IList, 
+    IReadOnlyList<TItem>, 
+    INotifyCollectionChanged,
     INotificationHandler<CollectionChanged<IEnumerable<TItem>>>
 {
-    private readonly IServiceFactory serviceFactory;
+    public ObservableCollection<TItem> collection = [];
     private readonly SynchronizationContext? context;
+    private readonly IServiceFactory serviceFactory;
 
-    public ObservableCollectionViewModel(IServiceFactory serviceFactory, 
+    public ObservableCollectionViewModel(IServiceFactory serviceFactory,
         IMediator mediator)
     {
         context = SynchronizationContext.Current;
 
         this.serviceFactory = serviceFactory;
         mediator.Subscribe(this);
+
+        collection.CollectionChanged += OnCollectionChanged;
     }
 
     public ObservableCollectionViewModel(IServiceFactory serviceFactory,
@@ -28,9 +37,56 @@ public class ObservableCollectionViewModel<TItem> :
         this.serviceFactory = serviceFactory;
         mediator.Subscribe(this);
 
+        collection.CollectionChanged += OnCollectionChanged;
+
         AddRange(items);
     }
 
+    public event NotifyCollectionChangedEventHandler? CollectionChanged;
+
+    public int Count => collection.Count;
+
+    bool IList.IsFixedSize => false;
+
+    bool ICollection<TItem>.IsReadOnly => false;
+
+    bool IList.IsReadOnly => false;
+
+    bool ICollection.IsSynchronized => false;
+
+    object ICollection.SyncRoot => this;
+
+    protected IList<TItem> Items => collection;
+
+    public TItem this[int index]
+    {
+        get => collection[index];
+        set
+        {
+            SetItem(index, value);
+        }
+    }
+
+    object? IList.this[int index]
+    {
+        get => collection[index];
+        set
+        {
+            TItem? item = default;
+
+            try
+            {
+                item = (TItem)value!;
+            }
+            catch (InvalidCastException)
+            {
+
+            }
+
+            this[index] = item!;
+        }
+    }
+
     public TItem Add()
     {
         TItem? item = serviceFactory.Create<TItem>();
@@ -58,6 +114,29 @@ public class ObservableCollectionViewModel<TItem> :
         return item;
     }
 
+    public void Add(TItem item)
+    {
+        int index = collection.Count;
+        InsertItem(index, item);
+    }
+
+    int IList.Add(object? value)
+    {
+        TItem? item = default;
+
+        try
+        {
+            item = (TItem)value!;
+        }
+        catch (InvalidCastException)
+        {
+
+        }
+
+        Add(item!);
+        return Count - 1;
+    }
+
     public void AddRange(IEnumerable<TItem> items)
     {
         foreach (TItem? item in items)
@@ -65,8 +144,21 @@ public class ObservableCollectionViewModel<TItem> :
             context?.Post(state => Add(item), null);
         }
     }
+    public void Clear() => ClearItems();
 
-    public ValueTask Handle(CollectionChanged<IEnumerable<TItem>> notification, 
+    public bool Contains(TItem item) => collection.Contains(item);
+
+    bool IList.Contains(object? value) => IsCompatibleObject(value) && Contains((TItem)value!);
+
+    public void CopyTo(TItem[] array, int index) => collection.CopyTo(array, index);
+
+    void ICollection.CopyTo(Array array, int index) => collection.CopyTo((TItem[])array, index);
+
+    public IEnumerator<TItem> GetEnumerator() => collection.GetEnumerator();
+
+    IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)collection).GetEnumerator();
+
+    public ValueTask Handle(CollectionChanged<IEnumerable<TItem>> notification,
         CancellationToken cancellationToken)
     {
         context?.Post(state => Clear(), null);
@@ -74,6 +166,55 @@ public class ObservableCollectionViewModel<TItem> :
 
         return ValueTask.CompletedTask;
     }
+
+    public int IndexOf(TItem item) => collection.IndexOf(item);
+
+    int IList.IndexOf(object? value) => IsCompatibleObject(value) ? IndexOf((TItem)value!) : -1;
+
+    public void Insert(int index, TItem item) => InsertItem(index, item);
+
+    void IList.Insert(int index, object? value)
+    {
+        if (value is TItem item)
+        {
+            Insert(index, item);
+        }
+    }
+
+    public bool Remove(TItem item)
+    {
+        int index = collection.IndexOf(item);
+        if (index < 0) return false;
+        RemoveItem(index);
+        return true;
+    }
+
+    void IList.Remove(object? value)
+    {
+        if (IsCompatibleObject(value))
+        {
+            Remove((TItem)value!);
+        }
+    }
+    public void RemoveAt(int index) => RemoveItem(index);
+
+    protected virtual void ClearItems() => collection.Clear();
+
+    protected virtual void InsertItem(int index, TItem value)
+    {
+        if (value is TItem item)
+        {
+            collection.Insert(index, item);
+        }
+    }
+
+    protected virtual void RemoveItem(int index) => collection.RemoveAt(index);
+
+    protected virtual void SetItem(int index, TItem item) => collection[index] = item;
+
+    private static bool IsCompatibleObject(object? value) => (value is TItem) || (value == null && default(TItem) == null);
+
+    private void OnCollectionChanged(object? sender, NotifyCollectionChangedEventArgs args) => CollectionChanged?.Invoke(this, args);
 }
 
 public class ObservableCollectionViewModel(IServiceFactory serviceFactory, IMediator mediator) :

Hyperbar/Views/WidgetContainerViewModel.cs

@@ -1,12 +1,18 @@
 
+using CommunityToolkit.Mvvm.ComponentModel;
+
 namespace Hyperbar;
 
-public class WidgetContainerViewModel(ITemplateFactory templateFactory,
+public partial class WidgetContainerViewModel(ITemplateFactory templateFactory,
     IServiceFactory serviceFactory,
     IMediator mediator,
-    IEnumerable<IWidgetViewModel> items) :
+    IEnumerable<IWidgetViewModel> items,
+    bool alternate) :
     ObservableCollectionViewModel<IWidgetViewModel>(serviceFactory, mediator, items),
     ITemplatedViewModel
 {
+    [ObservableProperty]
+    private bool alternate = alternate;
+
     public ITemplateFactory TemplateFactory => templateFactory;
 }