TreeView with VirtualToggleButtonaおよびPreviewMouseDown。奇妙な振る舞い

Question

私がthis articleを読んだ後、私はVirtualToggleButtonで遊ぶことにし、2つのブール型プロパティSuppressKeyboardとSuppressMouseを追加して、e.HandledをTrueに設定するかどうかを定義しました。

ここで変更VTBのためのコードがあります：

public static class VirtualToggleButton 
    { 
     #region attached properties 

     #region IsChecked 

     /// <summary> 
     /// IsChecked Attached Dependency Property 
     /// </summary> 
     public static readonly DependencyProperty IsCheckedProperty = 
      DependencyProperty.RegisterAttached("IsChecked", typeof(Nullable<bool>), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((Nullable<bool>)false, 
        FrameworkPropertyMetadataOptions.BindsTwoWayByDefault | FrameworkPropertyMetadataOptions.Journal, 
        new PropertyChangedCallback(OnIsCheckedChanged))); 

     /// <summary> 
     /// Gets the IsChecked property. This dependency property 
     /// indicates whether the toggle button is checked. 
     /// </summary> 
     public static Nullable<bool> GetIsChecked(DependencyObject d) 
     { 
      return (Nullable<bool>)d.GetValue(IsCheckedProperty); 
     } 

     /// <summary> 
     /// Sets the IsChecked property. This dependency property 
     /// indicates whether the toggle button is checked. 
     /// </summary> 
     public static void SetIsChecked(DependencyObject d, Nullable<bool> value) 
     { 
      d.SetValue(IsCheckedProperty, value); 
     } 

     /// <summary> 
     /// Handles changes to the IsChecked property. 
     /// </summary> 
     private static void OnIsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
     { 
      var pseudobutton = d as UIElement; 
      if (pseudobutton != null) 
      { 
       var newValue = (Nullable<bool>)e.NewValue; 
       if (newValue == true) 
       { 
        RaiseCheckedEvent(pseudobutton); 
       } 
       else if (newValue == false) 
       { 
        RaiseUncheckedEvent(pseudobutton); 
       } 
       else 
       { 
        RaiseIndeterminateEvent(pseudobutton); 
       } 
      } 
     } 

     #endregion 

     #region IsThreeState 

     /// <summary> 
     /// IsThreeState Attached Dependency Property 
     /// </summary> 
     public static readonly DependencyProperty IsThreeStateProperty = 
      DependencyProperty.RegisterAttached("IsThreeState", typeof(bool), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((bool)false)); 

     /// <summary> 
     /// Gets the IsThreeState property. This dependency property 
     /// indicates whether the control supports two or three states. 
     /// IsChecked can be set to null as a third state when IsThreeState is true. 
     /// </summary> 
     public static bool GetIsThreeState(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsThreeStateProperty); 
     } 

     /// <summary> 
     /// Sets the IsThreeState property. This dependency property 
     /// indicates whether the control supports two or three states. 
     /// IsChecked can be set to null as a third state when IsThreeState is true. 
     /// </summary> 
     public static void SetIsThreeState(DependencyObject d, bool value) 
     { 
      d.SetValue(IsThreeStateProperty, value); 
     } 

     #endregion 

     #region IsVirtualToggleButton 

     /// <summary> 
     /// IsVirtualToggleButton Attached Dependency Property 
     /// </summary> 
     public static readonly DependencyProperty IsVirtualToggleButtonProperty = 
      DependencyProperty.RegisterAttached("IsVirtualToggleButton", typeof(bool), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((bool)false, 
        new PropertyChangedCallback(OnIsVirtualToggleButtonChanged))); 

     /// <summary> 
     /// Gets the IsVirtualToggleButton property. This dependency property 
     /// indicates whether the object to which the property is attached is treated as a VirtualToggleButton. 
     /// If true, the object will respond to keyboard and mouse input the same way a ToggleButton would. 
     /// </summary> 
     public static bool GetIsVirtualToggleButton(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsVirtualToggleButtonProperty); 
     } 

     /// <summary> 
     /// Sets the IsVirtualToggleButton property. This dependency property 
     /// indicates whether the object to which the property is attached is treated as a VirtualToggleButton. 
     /// If true, the object will respond to keyboard and mouse input the same way a ToggleButton would. 
     /// </summary> 
     public static void SetIsVirtualToggleButton(DependencyObject d, bool value) 
     { 
      d.SetValue(IsVirtualToggleButtonProperty, value); 
     } 

     /// <summary> 
     /// Handles changes to the IsVirtualToggleButton property. 
     /// </summary> 
     private static void OnIsVirtualToggleButtonChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
     { 
      var element = d as IInputElement; 
      if (element != null) 
      { 
       if ((bool)e.NewValue) 
       { 
        element.AddHandler(Mouse.PreviewMouseDownEvent, new MouseButtonEventHandler(OnPreviewMouseLeftButtonDown)); 
        element.PreviewKeyDown += OnPreviewKeyDown; 
       } 
       else 
       { 
        element.RemoveHandler(Mouse.PreviewMouseDownEvent, new MouseButtonEventHandler(OnPreviewMouseLeftButtonDown)); 
        element.PreviewKeyDown -= OnPreviewKeyDown; 
       } 
      } 
     } 

     #endregion 

     #region SuppressKeyboard 

     public static readonly DependencyProperty SuppressKeyboardProperty = 
      DependencyProperty.RegisterAttached("SuppressKeyboard", typeof (bool), typeof (VirtualToggleButton), 
               new FrameworkPropertyMetadata(false)); 

     public static bool GetSuppressKeyboard(DependencyObject d) 
     { 
      return (bool)d.GetValue(SuppressKeyboardProperty); 
     } 

     public static void SetSuppressKeyboard(DependencyObject d, bool value) 
     { 
      d.SetValue(SuppressKeyboardProperty, value); 
     } 

     #endregion 

     #region SuppressMouse 

     public static readonly DependencyProperty SuppressMouseProperty = 
      DependencyProperty.RegisterAttached("SuppressMouse", typeof(bool), typeof(VirtualToggleButton), 
               new FrameworkPropertyMetadata(false)); 

     public static bool GetSuppressMouse(DependencyObject d) 
     { 
      return (bool)d.GetValue(SuppressMouseProperty); 
     } 

     public static void SetSuppressMouse(DependencyObject d, bool value) 
     { 
      d.SetValue(SuppressKeyboardProperty, value); 
     } 

     #endregion 

     #endregion 

     #region routed events 

     #region Checked 

     /// <summary> 
     /// A static helper method to raise the Checked event on a target element. 
     /// </summary> 
     /// <param name="target">UIElement or ContentElement on which to raise the event</param> 
     internal static RoutedEventArgs RaiseCheckedEvent(UIElement target) 
     { 
      if (target == null) 
       return null; 

      var args = new RoutedEventArgs {RoutedEvent = ToggleButton.CheckedEvent}; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #region Unchecked 

     /// <summary> 
     /// A static helper method to raise the Unchecked event on a target element. 
     /// </summary> 
     /// <param name="target">UIElement or ContentElement on which to raise the event</param> 
     internal static RoutedEventArgs RaiseUncheckedEvent(UIElement target) 
     { 
      if (target == null) return null; 

      RoutedEventArgs args = new RoutedEventArgs(); 
      args.RoutedEvent = ToggleButton.UncheckedEvent; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #region Indeterminate 

     /// <summary> 
     /// A static helper method to raise the Indeterminate event on a target element. 
     /// </summary> 
     /// <param name="target">UIElement or ContentElement on which to raise the event</param> 
     internal static RoutedEventArgs RaiseIndeterminateEvent(UIElement target) 
     { 
      if (target == null) return null; 

      RoutedEventArgs args = new RoutedEventArgs(); 
      args.RoutedEvent = ToggleButton.IndeterminateEvent; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #endregion 

     #region private methods 

     private static void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e) 
     { 
      if (e.ChangedButton == MouseButton.Left && e.LeftButton == MouseButtonState.Pressed) 
      { 
       UpdateIsChecked(sender as DependencyObject); 

       var dob = sender as DependencyObject; 
       var suppress = dob != null && GetSuppressMouse(dob); 
       e.Handled = suppress; 
      } 
     } 

     private static void OnPreviewKeyDown(object sender, KeyEventArgs e) 
     { 
      var dob = sender as DependencyObject; 
      var suppress = dob != null && GetSuppressKeyboard(dob); 

      if (e.OriginalSource == sender) 
      { 
       if (e.Key == Key.Space) 
       { 
        // ignore alt+space which invokes the system menu 
        if ((Keyboard.Modifiers & ModifierKeys.Alt) == ModifierKeys.Alt) 
         return; 

        UpdateIsChecked(sender as DependencyObject); 
        e.Handled = suppress; 
       } 
       else if (e.Key == Key.Enter && (bool)(sender as DependencyObject).GetValue(KeyboardNavigation.AcceptsReturnProperty)) 
       { 
        UpdateIsChecked(sender as DependencyObject); 
        e.Handled = suppress; 
       } 
      } 
     } 

     private static void UpdateIsChecked(DependencyObject d) 
     { 
      Nullable<bool> isChecked = GetIsChecked(d); 
      if (isChecked == true) 
      { 
       SetIsChecked(d, GetIsThreeState(d) ? (Nullable<bool>)null : (Nullable<bool>)false); 
      } 
      else 
      { 
       SetIsChecked(d, isChecked.HasValue); 
      } 
     } 

     private static void RaiseEvent(DependencyObject target, RoutedEventArgs args) 
     { 
      if (target is UIElement) 
      { 
       (target as UIElement).RaiseEvent(args); 
      } 
      else if (target is ContentElement) 
      { 
       (target as ContentElement).RaiseEvent(args); 
      } 
     } 

     #endregion 
    } 

私も少しバインディングを変更：

<TreeView> 
      <TreeView.Resources> 
       <Style TargetType="TreeViewItem"> 
        <Setter Property="IsExpanded" Value="True"/> 
        <Setter Property="cl:VirtualToggleButton.IsVirtualToggleButton" Value="True"/> 
        <Setter Property="cl:VirtualToggleButton.SuppressKeyboard" Value="True"/> 
        <!--<Setter Property="cl:VirtualToggleButton.SuppressMouse" Value="True"/>--> 
       </Style> 
      </TreeView.Resources> 

      <TreeView.ItemTemplate> 
       <HierarchicalDataTemplate ItemsSource="{Binding Softwares}"> 
        <TextBlock Text="{Binding Name}"/> 
        <HierarchicalDataTemplate.ItemTemplate> 
         <DataTemplate> 
          <StackPanel Orientation="Horizontal"> 
           <CheckBox Focusable="False" 
              IsChecked="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type TreeViewItem}} 
                    , Path=(cl:VirtualToggleButton.IsChecked), Mode=OneWay}"/> 
           <TextBlock Text="{Binding Name}" Height="Auto"/> 
          </StackPanel> 
         </DataTemplate> 
        </HierarchicalDataTemplate.ItemTemplate> 
       </HierarchicalDataTemplate> 
      </TreeView.ItemTemplate> 

     </TreeView> 

ここでは非常に奇妙なことが来ます。 SuppressMouseが設定されていて、TreeViewItemsがクリックされていない場合（これは一貫した動作です）、IsCheckedはTrueに設定されていますが、CheckBoxはチェックされません。 キーボードが使用されているとすべてがうまく動作するので、なぜそうなのかわかりません。 SuppressMouse = Falseの場合CheckBoxはその状態を変更しますが、クリックしたTreeViewItemに対してOnPreviewMouseLeftButtonDownが2回呼び出されます。そして、これも非常に混乱しています。

質問：説明動作

Answer 1

まあ、VirtualToggleButtonのオリジナルバージョンは、のMouseLeftButtonDownイベントをバブリング使用の原因は何ですか。 私が気に入らないのは、クリックされたコントロールがイベントを処理済みとしてマークするチャンスです。そして、特定の記事でTreeViewItemの選択がmousedownイベントハンドラを呼び出さない場合があります。そこで、私はトンネリングイベントを使用することに決めましたが、送信者とイベントのソースをチェックするのを忘れるバグを導入しました。ルートTreeViewItemは子アイテムがクリックされていたのに対し、Checkedとして状態を設定しました。

イベントが要素ツリーを介して伝播できるかどうかを制御するために、さらにいくつかのプロパティを追加しました。どのようにボタンがトグルされますか（キーボードまたはマウス）。

VTBの最終版：

public static class VirtualToggleButton 
    { 
     #region attached properties 

     #region IsChecked 

     public static readonly DependencyProperty IsCheckedProperty = 
      DependencyProperty.RegisterAttached("IsChecked", typeof(Nullable<bool>), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((Nullable<bool>)false, 
        FrameworkPropertyMetadataOptions.BindsTwoWayByDefault | FrameworkPropertyMetadataOptions.Journal, 
        new PropertyChangedCallback(OnIsCheckedChanged))); 

     /// <summary> 
     /// Gets the IsChecked property. This dependency property 
     /// indicates whether the toggle button is checked. 
     /// </summary> 
     public static Nullable<bool> GetIsChecked(DependencyObject d) 
     { 
      return (Nullable<bool>)d.GetValue(IsCheckedProperty); 
     } 

     /// <summary> 
     /// Sets the IsChecked property. This dependency property 
     /// indicates whether the toggle button is checked. 
     /// </summary> 
     public static void SetIsChecked(DependencyObject d, Nullable<bool> value) 
     { 
      d.SetValue(IsCheckedProperty, value); 
     } 

     /// <summary> 
     /// Handles changes to the IsChecked property. 
     /// </summary> 
     private static void OnIsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
     { 
      var pseudobutton = d as UIElement; 
      if (pseudobutton != null) 
      { 
       var newValue = (Nullable<bool>)e.NewValue; 
       if (newValue == true) 
       { 
        RaiseCheckedEvent(pseudobutton); 
       } 
       else if (newValue == false) 
       { 
        RaiseUncheckedEvent(pseudobutton); 
       } 
       else 
       { 
        RaiseIndeterminateEvent(pseudobutton); 
       } 
      } 
     } 

     #endregion 

     #region IsThreeState 

     /// <summary> 
     /// IsThreeState Attached Dependency Property 
     /// </summary> 
     public static readonly DependencyProperty IsThreeStateProperty = 
      DependencyProperty.RegisterAttached("IsThreeState", typeof(bool), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((bool)false)); 

     /// <summary> 
     /// Gets the IsThreeState property. This dependency property 
     /// indicates whether the control supports two or three states. 
     /// IsChecked can be set to null as a third state when IsThreeState is true. 
     /// </summary> 
     public static bool GetIsThreeState(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsThreeStateProperty); 
     } 

     /// <summary> 
     /// Sets the IsThreeState property. This dependency property 
     /// indicates whether the control supports two or three states. 
     /// IsChecked can be set to null as a third state when IsThreeState is true. 
     /// </summary> 
     public static void SetIsThreeState(DependencyObject d, bool value) 
     { 
      d.SetValue(IsThreeStateProperty, value); 
     } 

     #endregion 

     #region IsVirtualToggleButton 

     /// <summary> 
     /// IsVirtualToggleButton Attached Dependency Property 
     /// </summary> 
     public static readonly DependencyProperty IsVirtualToggleButtonProperty = 
      DependencyProperty.RegisterAttached("IsVirtualToggleButton", typeof(bool), typeof(VirtualToggleButton), 
       new FrameworkPropertyMetadata((bool)false, 
        new PropertyChangedCallback(OnIsVirtualToggleButtonChanged))); 

     /// <summary> 
     /// Gets the IsVirtualToggleButton property. This dependency property 
     /// indicates whether the object to which the property is attached is treated as a VirtualToggleButton. 
     /// If true, the object will respond to keyboard and mouse input the same way a ToggleButton would. 
     /// </summary> 
     public static bool GetIsVirtualToggleButton(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsVirtualToggleButtonProperty); 
     } 

     /// <summary> 
     /// Sets the IsVirtualToggleButton property. This dependency property 
     /// indicates whether the object to which the property is attached is treated as a VirtualToggleButton. 
     /// If true, the object will respond to keyboard and mouse input the same way a ToggleButton would. 
     /// </summary> 
     public static void SetIsVirtualToggleButton(DependencyObject d, bool value) 
     { 
      d.SetValue(IsVirtualToggleButtonProperty, value); 
     } 

     /// <summary> 
     /// Handles changes to the IsVirtualToggleButton property. 
     /// </summary> 
     private static void OnIsVirtualToggleButtonChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
     { 
      var element = d as IInputElement; 
      if (element != null) 
      { 
       if ((bool)e.NewValue) 
       { 
        element.AddHandler(Mouse.PreviewMouseDownEvent, new MouseButtonEventHandler(OnPrevieMouseLeftButtonDown)); 
        element.PreviewKeyDown += OnPreviewKeyDown; 
       } 
       else 
       { 
        element.RemoveHandler(Mouse.PreviewMouseDownEvent, new MouseButtonEventHandler(OnPrevieMouseLeftButtonDown)); 
        element.PreviewKeyDown -= OnPreviewKeyDown; 
       } 
      } 
     } 

     #endregion 

     #region SuppressKeyboard 

     public static readonly DependencyProperty SuppressKeyboardProperty = 
      DependencyProperty.RegisterAttached("SuppressKeyboard", typeof(bool), typeof(VirtualToggleButton), 
               new FrameworkPropertyMetadata(false)); 

     public static bool GetSuppressKeyboard(DependencyObject d) 
     { 
      return (bool)d.GetValue(SuppressKeyboardProperty); 
     } 

     public static void SetSuppressKeyboard(DependencyObject d, bool value) 
     { 
      d.SetValue(SuppressKeyboardProperty, value); 
     } 

     #endregion 

     #region SuppressMouse 

     public static readonly DependencyProperty SuppressMouseProperty = 
      DependencyProperty.RegisterAttached("SuppressMouse", typeof(bool), typeof(VirtualToggleButton), 
               new FrameworkPropertyMetadata(false)); 

     public static bool GetSuppressMouse(DependencyObject d) 
     { 
      return (bool)d.GetValue(SuppressMouseProperty); 
     } 

     public static void SetSuppressMouse(DependencyObject d, bool value) 
     { 
      d.SetValue(SuppressKeyboardProperty, value); 
     } 

     #endregion 

     #region IsToggledByMouse 

     public static readonly DependencyProperty IsToggledByMouseProperty = 
      DependencyProperty.RegisterAttached("IsToggledByMouse", typeof(bool), typeof(VirtualToggleButton), 
               new FrameworkPropertyMetadata(true)); 

     public static bool GetIsToggledByMouse(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsToggledByMouseProperty); 
     } 

     public static void SetIsToggledByMouse(DependencyObject d, bool value) 
     { 
      d.SetValue(IsToggledByMouseProperty, value); 
     } 

     #endregion 

     #region IsToogledByKeyboard 

     public static readonly DependencyProperty IsToggledByKeyboardProperty = 
      DependencyProperty.RegisterAttached("IsToggledByKeyboard", typeof(bool), typeof(VirtualToggleButton), 
               new FrameworkPropertyMetadata(true)); 

     public static bool GetIsToggledByKeyboard(DependencyObject d) 
     { 
      return (bool)d.GetValue(IsToggledByKeyboardProperty); 
     } 

     public static void SetIsToggledByKeyboard(DependencyObject d, bool value) 
     { 
      d.SetValue(IsToggledByKeyboardProperty, value); 
     } 

     #endregion 

     #endregion 

     #region routed events 

     #region Checked 

     internal static RoutedEventArgs RaiseCheckedEvent(UIElement target) 
     { 
      if (target == null) 
       return null; 

      var args = new RoutedEventArgs { RoutedEvent = ToggleButton.CheckedEvent }; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #region Unchecked 

     /// <summary> 
     /// A static helper method to raise the Unchecked event on a target element. 
     /// </summary> 
     /// <param name="target">UIElement or ContentElement on which to raise the event</param> 
     internal static RoutedEventArgs RaiseUncheckedEvent(UIElement target) 
     { 
      if (target == null) return null; 

      RoutedEventArgs args = new RoutedEventArgs(); 
      args.RoutedEvent = ToggleButton.UncheckedEvent; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #region Indeterminate 

     /// <summary> 
     /// A static helper method to raise the Indeterminate event on a target element. 
     /// </summary> 
     /// <param name="target">UIElement or ContentElement on which to raise the event</param> 
     internal static RoutedEventArgs RaiseIndeterminateEvent(UIElement target) 
     { 
      if (target == null) return null; 

      RoutedEventArgs args = new RoutedEventArgs(); 
      args.RoutedEvent = ToggleButton.IndeterminateEvent; 
      RaiseEvent(target, args); 
      return args; 
     } 

     #endregion 

     #endregion 

     #region private methods 

     private static void OnPrevieMouseLeftButtonDown(object sender, MouseButtonEventArgs e) 
     { 
      // Looking for the logically closest (up in elements tree) element 
      // Like a bubble in a tunneling event 
      var senderType = sender.GetType(); 
      var depObj = e.OriginalSource as DependencyObject; 
      while (depObj != null && depObj.GetType() != senderType) 
       depObj = VisualTreeHelper.GetParent(depObj); 

      if (depObj != sender) 
       return; 

      if (e.ChangedButton == MouseButton.Left && e.LeftButton == MouseButtonState.Pressed) 
      { 
       var dob = sender as DependencyObject; 
       var suppress = dob != null && GetSuppressMouse(dob); 
       e.Handled = suppress; 

       if (!GetIsToggledByMouse(depObj)) 
        return; 

       UpdateIsChecked(sender as DependencyObject); 
      } 
     } 

     private static void OnPreviewKeyDown(object sender, KeyEventArgs e) 
     { 
      if (e.Key != Key.Space && e.Key != Key.Enter) 
       return; 

      var senderType = sender.GetType(); 
      var p = e.OriginalSource as DependencyObject; 
      while (p != null && p.GetType() != senderType) 
       p = VisualTreeHelper.GetParent(p); 

      if (p != sender) 
       return; 

      var dob = sender as DependencyObject; 
      var suppress = dob != null && GetSuppressKeyboard(dob); 

      if (e.Key == Key.Space) 
      { 
       // ignore alt+space which invokes the system menu 
       if ((Keyboard.Modifiers & ModifierKeys.Alt) == ModifierKeys.Alt) 
        return; 

       UpdateIsChecked(sender as DependencyObject); 
       e.Handled = suppress; 
      } 
      else if (e.Key == Key.Enter && (bool)(sender as DependencyObject).GetValue(KeyboardNavigation.AcceptsReturnProperty)) 
      { 
       UpdateIsChecked(sender as DependencyObject); 
       e.Handled = suppress; 
      } 

     } 

     private static void UpdateIsChecked(DependencyObject d) 
     { 
      Nullable<bool> isChecked = GetIsChecked(d); 
      if (isChecked == true) 
      { 
       SetIsChecked(d, GetIsThreeState(d) ? (Nullable<bool>)null : (Nullable<bool>)false); 
      } 
      else 
      { 
       SetIsChecked(d, isChecked.HasValue); 
      } 
     } 

     private static void RaiseEvent(DependencyObject target, RoutedEventArgs args) 
     { 
      if (target is UIElement) 
      { 
       (target as UIElement).RaiseEvent(args); 
      } 
      else if (target is ContentElement) 
      { 
       (target as ContentElement).RaiseEvent(args); 
      } 
     } 

     #endregion 
    }