Adding example failing tests

Fixing minor code issue

Author: Keboo

src/MaterialDesignThemes.Wpf/TreeListView.cs

@@ -20,7 +20,7 @@ public double LevelIndentSize
 
     internal TreeListViewItemsCollection? InternalItemsSource { get; set; }
 
-    internal bool IsCollapsingItem { get; set; } = false;
+    private bool IsCollapsingItem { get; set; }
     public new IList SelectedItems
     {
         get => (IList)GetValue(SelectedItemsProperty);
@@ -88,16 +88,13 @@ private void TreeListView_SelectionChanged(object sender, SelectionChangedEventA
         // Add newly selected
         foreach (var item in e.AddedItems)
         {
-            if (!SelectedItems.Contains(item))
-            {
-                SelectedItems.Add(item);
-            }
+            SelectedItems.Add(item);
         }
     }
 
     private void SelectedItems_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
     {
-        // NB: Everytime we modify the base.SelectedItems we have to unsubscribe from the SelectionChanged event
+        // NB: Every time we modify the base.SelectedItems we have to unsubscribe from the SelectionChanged event
         //     The base.SelectedItems only contains the visually selected items,
         //     while the SelectedItems contains all selected items, even ones which are not "visible"
         this.SelectionChanged -= TreeListView_SelectionChanged;
@@ -122,10 +119,7 @@ private void SelectedItems_CollectionChanged(object? sender, NotifyCollectionCha
 
             foreach (var item in e.NewItems ?? Array.Empty<object>())
             {
-                if (!base.SelectedItems.Contains(item))
-                {
-                    base.SelectedItems.Add(item);
-                }
+                base.SelectedItems.Add(item);
             }
         }
 
@@ -210,7 +204,7 @@ internal void ItemExpandedChanged(TreeListViewItem item)
                 {
                     itemsSource.InsertWithLevel(i + index + 1, children[i], parentLevel + 1);
                 }
-                // if a node, which has a selected childs, is expanded (added) we need to visually select the child (i.e.: update base.SelectedItems)
+                // if a node, which has a selected child, is expanded (added) we need to visually select the child (i.e.: update base.SelectedItems)
                 SyncUISelectionWithSelectedItems();
             }
             else
@@ -343,7 +337,7 @@ static int GetChildrenAndGrandChildrenCountOfPriorSiblings(TreeListViewItemsColl
 
     private List<object?> GetExpandedChildrenAndGrandChildren(object? dataItem)
     {
-        List<object?> expandedChildren = new();
+        List<object?> expandedChildren = [];
         if (dataItem is null || ItemContainerGenerator.ContainerFromItem(dataItem) is not TreeListViewItem { IsExpanded: true } container)
             return expandedChildren;
 

tests/MaterialDesignThemes.UITests/WPF/TreeListViews/TreeListViewDataBinding.xaml

@@ -32,6 +32,7 @@
     <StackPanel Grid.Row="1" Orientation="Horizontal">
       <Button Content="Add" Click="Add_OnClick" />
       <Button Content="Add with Children" Click="AddWithChildren_OnClick" />
+      <Button Content="Add Duplicate" Click="AddDuplicate_OnClick" />
       <Button Content="Remove" Click="Remove_OnClick" />
       <Button Content="Replace" Click="Replace_OnClick" />
       <Button Content="Down" Click="MoveDown_OnClick" />

tests/MaterialDesignThemes.UITests/WPF/TreeListViews/TreeListViewDataBinding.xaml.cs

@@ -21,6 +21,7 @@ public TreeListViewDataBinding()
 
     public void Add_OnClick(object sender, EventArgs e) => AddItem();
     public void AddWithChildren_OnClick(object sender, EventArgs e) => AddItemWithChildren();
+    public void AddDuplicate_OnClick(object sender, EventArgs e) => AddDuplicateItem();
 
     private void AddItem()
     {
@@ -34,6 +35,23 @@ private void AddItem()
         }
     }
 
+    private void AddDuplicateItem()
+    {
+        if (TreeListView.SelectedItem is TreeItem selectedItem)
+        {
+            if (selectedItem.Parent is { } parent)
+            {
+                int childIndex = parent.Children.IndexOf(selectedItem);
+                parent.Children.Insert(childIndex + 1, selectedItem);
+            }
+            else
+            {
+                int itemIndex = Items.IndexOf(selectedItem);
+                Items.Insert(itemIndex + 1, selectedItem);
+            }
+        }
+    }
+
     private void AddItemWithChildren()
     {
         TreeItem parent = new(Items.Count.ToString(), null)

tests/MaterialDesignThemes.UITests/WPF/TreeListViews/TreeListViewImplicitTemplate.xaml.cs

@@ -41,12 +41,9 @@ public void Remove_OnClick(object sender, EventArgs e)
         }
     }
 
-    private void RemoveItem(IList<TreeItem> items, TreeItem toRemove)
+    private static void RemoveItem(IList<TreeItem> items, TreeItem toRemove)
     {
-        if (items.Contains(toRemove))
-        {
-            items.Remove(toRemove);
-        }
+        items.Remove(toRemove);
         foreach (TreeItem item in items)
         {
             RemoveItem(item.Children, toRemove);

tests/MaterialDesignThemes.UITests/WPF/TreeListViews/TreeListViewTests.cs

@@ -1,4 +1,3 @@
-using System.Collections;
 using System.ComponentModel;
 using System.Windows.Media;
 
@@ -1118,6 +1117,102 @@ static void AssertSelectedItems(TreeListView treeListView)
         }
     }
 
+    [Fact]
+    public async Task TreeListView_CollapsingParentAndMovingSelection_ClearsSelectionsFromHiddenChildNode()
+    {
+        await using var recorder = new TestRecorder(App);
+
+        IVisualElement<Grid> root = (await LoadUserControl(typeof(TreeListViewDataBinding))).As<Grid>();
+        IVisualElement<TreeListView> treeListView = await root.GetElement<TreeListView>();
+        IVisualElement<Button> addButton = await root.GetElement(ElementQuery.PropertyExpression<Button>(x => x.Content, "Add"));
+
+        IVisualElement<TreeListViewItem> item1 = await treeListView.GetElement<TreeListViewItem>("/TreeListViewItem[1]");
+        IVisualElement<TreeListViewItem> item2 = await treeListView.GetElement<TreeListViewItem>("/TreeListViewItem[2]");
+
+        // add three children to the second item
+        await AddChildren(item2, 3, addButton);
+
+        // Expand the second item
+        await item2.LeftClickExpander();
+        await Task.Delay(50);
+
+        // select the second child
+        IVisualElement<TreeListViewItem> child2 = await treeListView.GetElement<TreeListViewItem>("/TreeListViewItem[4]");
+        await child2.LeftClick();
+
+        // Collapse the parent item
+        await item2.LeftClickExpander();
+        await Task.Delay(50);
+
+        // Left click on item 1, this should cause the previous selection to clear
+        await item1.LeftClick();
+        await Task.Delay(50);
+
+        await treeListView.RemoteExecute(AssertSelectedItems);
+
+        recorder.Success();
+
+        // Assert inside of the remote executed method because we can't return an IList, since it's not serializable
+        static void AssertSelectedItems(TreeListView treeListView)
+        {
+            var viewModel = (TreeListViewDataBinding)treeListView.DataContext;
+
+            Assert.Equal(["1"], viewModel.SelectedItems.Select(x => x.Value));
+        }
+    }
+
+    [Fact]
+    public async Task TreeListView_AddingDuplicateItemsAndSelectingWithArrowKeys_SelectsEachItemInTurn()
+    {
+        await using var recorder = new TestRecorder(App);
+
+        IVisualElement<Grid> root = (await LoadUserControl(typeof(TreeListViewDataBinding))).As<Grid>();
+        IVisualElement<TreeListView> treeListView = await root.GetElement<TreeListView>();
+        IVisualElement<Button> addDuplicateButton = await root.GetElement(ElementQuery.PropertyExpression<Button>(x => x.Content, "Add Duplicate"));
+
+        IVisualElement<TreeListViewItem> item1 = await treeListView.GetElement<TreeListViewItem>("/TreeListViewItem[1]");
+
+        // Left click on item 1 to select it
+        await item1.LeftClick();
+        await Task.Delay(50);
+
+        // Add two duplicates to the tree
+        await addDuplicateButton.LeftClick();
+        await Task.Delay(50);
+
+        await addDuplicateButton.LeftClick();
+        await Task.Delay(50);
+
+        IVisualElement<TreeListViewItem> item = await treeListView.GetElement<TreeListViewItem>($"/TreeListViewItem[0]");
+        await item.LeftClick();
+        await Task.Delay(50);
+
+        await treeListView.RemoteExecute(AssertSelectedItems, "0");
+
+        for(int i = 0; i < 2; i++)
+        {
+            // Press down arrow to select the next item
+            await treeListView.SendKeyboardInput($"{Key.Down}");
+            await Task.Delay(50);
+            await treeListView.RemoteExecute(AssertSelectedItems, "1");
+        }
+
+        await treeListView.SendKeyboardInput($"{Key.Down}");
+        await Task.Delay(50);
+        await treeListView.RemoteExecute(AssertSelectedItems, "2");
+
+        recorder.Success();
+
+        // Assert inside of the remote executed method because we can't return an IList, since it's not serializable
+        static void AssertSelectedItems(TreeListView treeListView, string expected)
+        {
+            var viewModel = (TreeListViewDataBinding)treeListView.DataContext;
+
+            Assert.Equal([expected], viewModel.SelectedItems.Select(x => x.Value));
+        }
+    }
+
+    
     private static async Task AssertTreeItemContent(IVisualElement<TreeListView> treeListView, int index, string content, bool isExpanded = false)
     {
         await Wait.For(async () =>

tests/MaterialDesignThemes.UITests/WPF/TreeListViews/TreeListViewWithCollectionView.xaml.cs

@@ -9,7 +9,7 @@ namespace MaterialDesignThemes.UITests.WPF.TreeListViews;
 /// </summary>
 public partial class TreeListViewWithCollectionView : UserControl
 {
-    private ObservableCollection<TreeItem> ItemsSource { get; } = new();
+    private ObservableCollection<TreeItem> ItemsSource { get; } = [];
 
     public ICollectionView Items { get; }