如何在單擊項目上單擊展開WPF TreeView

Question

現在，您必須雙擊或單擊+圖標。如果用戶點擊擴展的節點上的任何位置，是否有任何方法可以實現這一點？

Answer 1

也許不是最完美的解決方案，但這個工程：

static DependencyObject VisualUpwardSearch<T>(DependencyObject source) 
    { 
     while (source != null && source.GetType() != typeof(T)) 
      source = VisualTreeHelper.GetParent(source); 

     return source; 
    } 

然後在TreeViewItem.Selected處理程序：

 private void Treeview_Selected(object sender, RoutedEventArgs e) 
     { 
      var treeViewItem = VisualUpwardSearch<TreeViewItem>(e.OriginalSource as DependencyObject) as TreeViewItem; 
      if (treeViewItem != null) treeViewItem.IsExpanded = true; 
     } 

的VisualUpwardSearch魔術就是從這裏取：Select TreeView Node on right click before displaying ContextMenu

問候

Answer 2

我有這個相同的問題和f由於another StackOverflow post，我們找到了一個很好的解決方案。

在control.xaml的TreeView的元素，你可以直接掛接到TreeViewItem的Selected事件：

<TreeView ItemsSource="{StaticResource Array}" TreeViewItem.Selected="TreeViewItem_Selected"/> 

然後在你的control.xaml.cs後面的代碼，你可以從RoutedEventArgs搶選定樹型視圖和將其設置爲IsExpanded：

private void TreeViewItem_Selected(object sender, RoutedEventArgs e) 
{ 
    TreeViewItem tvi = e.OriginalSource as TreeViewItem; 

    if (tvi == null || e.Handled) return; 

    tvi.IsExpanded = !tvi.IsExpanded; 
    e.Handled = true; 
} 

乾淨整潔。希望能幫助別人！

Answer 3

當您使用鍵盤進行導航時，接受的解決方案具有奇怪的行爲，並且當它已被選中時不會摺疊該項目。或者，只需從TreeViewItem派生一個新類並重寫MouseLeftButtonDown方法。您還需要將您的TreeView.ItemsSource設置爲您的新TreeViewItem類的集合。

protected override void OnMouseLeftButtonDown(System.Windows.Input.MouseButtonEventArgs e) 
{ 
    if (!e.Handled && base.IsEnabled) 
    { 
     this.IsExpanded = !this.IsExpanded; 
     e.Handled = true; 
    } 
    base.OnMouseLeftButtonDown(e); 
} 

Answer 4

我有同樣的問題，我用Style的功能，所以你不需要處理事件。

我定義了一個樣式爲樹型視圖

<Style x:Key="{x:Type TreeViewItem}" TargetType="{x:Type TreeViewItem}"> 
    <!--<Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>--> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate TargetType="{x:Type TreeViewItem}"> 
         <CheckBox Style="{StaticResource TreeViewItemCB}" IsChecked="{Binding Path=IsExpanded,Mode=OneWayToSource,RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"> 
          <Grid Background="{StaticResource TreeViewItemBackground}" Margin="0"> 
          <Grid.RowDefinitions> 
           <RowDefinition Height="Auto"/> 
           <RowDefinition/> 
          </Grid.RowDefinitions> 
          <Border Name="Bd"> 
            <ContentPresenter x:Name="PART_Header" ContentSource="Header"/> 
          </Border> 
          <ItemsPresenter x:Name="ItemsHost" Grid.Row="1"/> 
          </Grid> 
         </CheckBox> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style> 

的重要組成部分，是定義在ControlTemplate中的複選框，並與之結合。選中CheckBox後，只需單擊一次即可展開該項目。

<CheckBox Style="{StaticResource TreeViewItemCB}" IsChecked="{Binding Path=IsExpanded,Mode=OneWayToSource,RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"> 

這是checkBox的樣式，因此它可以延伸並且不會顯示帶有筆觸的框。

<Style x:Key="TreeViewItemCB" TargetType="CheckBox" BasedOn="{StaticResource baseStyle}"> 
    <Setter Property="SnapsToDevicePixels" Value="true"/> 
    <Setter Property="OverridesDefaultStyle" Value="true"/> 
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" /> 
    <Setter Property="Background" Value="Transparent"/> 
    <Setter Property="VerticalAlignment" Value="Stretch"/> 
    <Setter Property="HorizontalAlignment" Value="Stretch"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate TargetType="CheckBox"> 
       <ContentPresenter VerticalAlignment="Stretch" HorizontalAlignment="Stretch" RecognizesAccessKey="True"/> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style> 

Answer 5

<TreeView.ItemContainerStyle> 
    <Style TargetType="{x:Type TreeViewItem}"> 
    <Setter Property="Cursor" Value="Hand" /> 
    <EventSetter Event="MouseUp" Handler="TreeViewItem_Click"/> 
    </Style> 
</TreeView.ItemContainerStyle> 


private void TreeViewItem_Click(object sender, MouseButtonEventArgs e) 
     { 
      ((TreeViewItem) sender).IsExpanded = !((TreeViewItem) sender).IsExpanded; 
      Thread.Sleep(700); 
     } 

這裏是答案，享受它

答：阿里Rahimy

Answer 6

另一種計算策略是使用附加propperties。

public class VirtualOneClickExpandButtonBehavior : DependencyObject 
{ 
    public static bool GetEnabled(DependencyObject obj) 
    { 
     return (bool)obj.GetValue(EnabledProperty); 
    } 

    public static void SetEnabled(DependencyObject obj, bool value) 
    { 
     obj.SetValue(EnabledProperty, value); 
    } 


    public static readonly DependencyProperty EnabledProperty = 
     DependencyProperty.RegisterAttached("Enabled", typeof(bool), typeof(VirtualOneClickExpandButtonBehavior), 
      new UIPropertyMetadata(false, EnabledPropertyChangedCallback 
       )); 

    private static void EnabledPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs) 
    { 
     var treeView = dependencyObject as TreeView; 

     if (treeView == null) return; 

     treeView.MouseUp += TreeView_MouseUp; 
    } 

    private static void TreeView_MouseUp(object sender, System.Windows.Input.MouseButtonEventArgs e) 
    { 
     var treeViewItem = VisualUpwardSearch<TreeViewItem>(e.OriginalSource as DependencyObject) as TreeViewItem; 
     if (treeViewItem != null) treeViewItem.IsExpanded = !treeViewItem.IsExpanded; 
    } 

    static DependencyObject VisualUpwardSearch<T>(DependencyObject source) 
    { 
     while (source != null && source.GetType() != typeof(T)) 
      source = VisualTreeHelper.GetParent(source); 

     return source; 
    } 
} 

然後你可以像這樣使用它。

<TreeView controls:VirtualOneClickExpandButtonBehavior.Enabled="true" ItemsSource="{Binding HierarchicalModel}"/> 

如果您使用MVVM模式，因爲您不需要隱藏代碼，這是一個不錯的選擇。

而且他對Markust的VisualUpwardSearch（DependencyObject源）