Merge pull request #2694 from KvanTTT/extend-listbox-and-treeview-sample

Extend ListBox and TreeView samples

samples/ControlCatalog/Pages/ListBoxPage.xaml

@@ -9,7 +9,20 @@
               Margin="0,16,0,0"
               HorizontalAlignment="Center"
               Spacing="16">
-      <ListBox Items="{Binding}" Width="250" Height="350"></ListBox>
+      <StackPanel Orientation="Vertical" Spacing="8">
+        <ListBox Items="{Binding Items}" SelectedItems="{Binding SelectedItems}" SelectionMode="{Binding SelectionMode}" Width="250" Height="350"></ListBox>
+
+        <Button Command="{Binding AddItemCommand}">Add</Button>
+
+        <Button Command="{Binding RemoveItemCommand}">Remove</Button>
+
+        <ComboBox SelectedIndex="{Binding SelectionMode, Mode=TwoWay}">
+          <ComboBoxItem>Single</ComboBoxItem>
+          <ComboBoxItem>Multiple</ComboBoxItem>
+          <ComboBoxItem>Toggle</ComboBoxItem>
+          <ComboBoxItem>AlwaysSelected</ComboBoxItem>
+        </ComboBox>
+      </StackPanel>
     </StackPanel>
   </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/ListBoxPage.xaml.cs

@@ -1,9 +1,9 @@
-using System;
-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
+using System.Reactive;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
+using ReactiveUI;
 
 namespace ControlCatalog.Pages
 {
@@ -11,9 +11,8 @@ namespace ControlCatalog.Pages
     {
         public ListBoxPage()
         {
-            this.InitializeComponent();
-            DataContext = Enumerable.Range(1, 10).Select(i => $"Item {i}" )
-                .ToArray();
+            InitializeComponent();
+            DataContext = new PageViewModel();
         }
 
         private void InitializeComponent()
@@ -21,5 +20,46 @@ namespace ControlCatalog.Pages
             AvaloniaXamlLoader.Load(this);
         }
 
+        private class PageViewModel : ReactiveObject
+        {
+            private int _counter;
+            private SelectionMode _selectionMode;
+
+            public PageViewModel()
+            {
+                Items = new ObservableCollection<string>(Enumerable.Range(1, 10).Select(i => GenerateItem()));
+                SelectedItems = new ObservableCollection<string>();
+
+                AddItemCommand = ReactiveCommand.Create(() => Items.Add(GenerateItem()));
+
+                RemoveItemCommand = ReactiveCommand.Create(() =>
+                {
+                    while (SelectedItems.Count > 0)
+                    {
+                        Items.Remove(SelectedItems[0]);
+                    }
+                });
+            }
+
+            public ObservableCollection<string> Items { get; }
+
+            public ObservableCollection<string> SelectedItems { get; }
+
+            public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
+
+            public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+
+            public SelectionMode SelectionMode
+            {
+                get => _selectionMode;
+                set
+                {
+                    SelectedItems.Clear();
+                    this.RaiseAndSetIfChanged(ref _selectionMode, value);
+                }
+            }
+
+            private string GenerateItem() => $"Item {_counter++}";
+        }
     }
 }

samples/ControlCatalog/Pages/TreeViewPage.xaml

@@ -6,16 +6,29 @@
     <TextBlock Classes="h2">Displays a hierachical tree of data.</TextBlock>
 
     <StackPanel Orientation="Horizontal"
-              Margin="0,16,0,0"
-              HorizontalAlignment="Center"
-              Spacing="16">
-      <TreeView SelectionMode="Multiple" Items="{Binding}" Width="250" Height="350">
-        <TreeView.ItemTemplate>
-          <TreeDataTemplate ItemsSource="{Binding Children}">
-            <TextBlock Text="{Binding Header}"/>
-          </TreeDataTemplate>
-        </TreeView.ItemTemplate>
-      </TreeView>
+                Margin="0,16,0,0"
+                HorizontalAlignment="Center"
+                Spacing="16">
+      <StackPanel Orientation="Vertical" Spacing="8">
+        <TreeView Items="{Binding Items}" SelectedItems="{Binding SelectedItems}" SelectionMode="{Binding SelectionMode}" Width="250" Height="350">
+          <TreeView.ItemTemplate>
+            <TreeDataTemplate ItemsSource="{Binding Children}">
+              <TextBlock Text="{Binding Header}"/>
+            </TreeDataTemplate>
+          </TreeView.ItemTemplate>
+        </TreeView>
+
+        <Button Command="{Binding AddItemCommand}">Add</Button>
+
+        <Button Command="{Binding RemoveItemCommand}">Remove</Button>
+
+        <ComboBox SelectedIndex="{Binding SelectionMode, Mode=TwoWay}">
+          <ComboBoxItem>Single</ComboBoxItem>
+          <ComboBoxItem>Multiple</ComboBoxItem>
+          <ComboBoxItem>Toggle</ComboBoxItem>
+          <ComboBoxItem>AlwaysSelected</ComboBoxItem>
+        </ComboBox>
+      </StackPanel>
     </StackPanel>
   </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/TreeViewPage.xaml.cs

@@ -1,8 +1,9 @@
-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
+using System.Reactive;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
+using ReactiveUI;
 
 namespace ControlCatalog.Pages
 {
@@ -10,8 +11,8 @@ namespace ControlCatalog.Pages
     {
         public TreeViewPage()
         {
-            this.InitializeComponent();
-            DataContext = new Node().Children;
+            InitializeComponent();
+            DataContext = new PageViewModel();
         }
 
         private void InitializeComponent()
@@ -19,22 +20,96 @@ namespace ControlCatalog.Pages
             AvaloniaXamlLoader.Load(this);
         }
 
-        public class Node
+        private class PageViewModel : ReactiveObject
         {
-            private IList<Node> _children;
+            private SelectionMode _selectionMode;
+
+            public PageViewModel()
+            {
+                Node root = new Node();
+                Items = root.Children;
+                SelectedItems = new ObservableCollection<Node>();
+
+                AddItemCommand = ReactiveCommand.Create(() =>
+                {
+                    Node parentItem = SelectedItems.Count > 0 ? SelectedItems[0] : root;
+                    parentItem.AddNewItem();
+                });
+
+                RemoveItemCommand = ReactiveCommand.Create(() =>
+                {
+                    while (SelectedItems.Count > 0)
+                    {
+                        Node lastItem = SelectedItems[0];
+                        RecursiveRemove(Items, lastItem);
+                        SelectedItems.Remove(lastItem);
+                    }
+
+                    bool RecursiveRemove(ObservableCollection<Node> items, Node selectedItem)
+                    {
+                        if (items.Remove(selectedItem))
+                        {
+                            return true;
+                        }
+
+                        foreach (Node item in items)
+                        {
+                            if (item.AreChildrenInitialized && RecursiveRemove(item.Children, selectedItem))
+                            {
+                                return true;
+                            }
+                        }
+
+                        return false;
+                    }
+                });
+            }
+
+            public ObservableCollection<Node> Items { get; }
+
+            public ObservableCollection<Node> SelectedItems { get; }
+
+            public ReactiveCommand<Unit, Unit> AddItemCommand { get; }
+
+            public ReactiveCommand<Unit, Unit> RemoveItemCommand { get; }
+
+            public SelectionMode SelectionMode
+            {
+                get => _selectionMode;
+                set
+                {
+                    SelectedItems.Clear();
+                    this.RaiseAndSetIfChanged(ref _selectionMode, value);
+                }
+            }
+        }
+
+        private class Node
+        {
+            private int _counter;
+            private ObservableCollection<Node> _children;
+
             public string Header { get; private set; }
-            public IList<Node> Children
+
+            public bool AreChildrenInitialized => _children != null;
+
+            public ObservableCollection<Node> Children
             {
                 get
                 {
                     if (_children == null)
                     {
-                        _children = Enumerable.Range(1, 10).Select(i => new Node() {Header = $"Item {i}"})
-                            .ToArray();
+                        _children = new ObservableCollection<Node>(Enumerable.Range(1, 10).Select(i => CreateNewNode()));
                     }
                     return _children;
                 }
             }
+
+            public void AddNewItem() => Children.Add(CreateNewNode());
+
+            public override string ToString() => Header;
+
+            private Node CreateNewNode() => new Node {Header = $"Item {_counter++}"};
         }
     }
 }