WPF TreeView的多個展開按鈕

Question

過去幾年我一直在閱讀這裏的問題和答案，但這是我無法準確找到所需內容後的第一個問題。

我正在創建一個WPF MVVM應用程序。 在這個應用程序中，我使用了一個TreeView，其中的每個節點都是兩個對象的組合（讓我們假設字符串）。

我想補充另一個展開按鈕，從節點左側的原始的一個，和另一個從節點的右側。

我想添加一個按鈕到TreeViewItem標題，但我不明白（搜索後）如何將他綁定到擴展操作。

很想聽到一些想法......

Answer 1

所以，如果我們去看看在default template爲x:Key="{x:Type TreeViewItem}"我們有一個ToggleButton這樣看;

<ToggleButton x:Name="Expander" 
         Style="{StaticResource ExpandCollapseToggleStyle}" 
         ClickMode="Press" 
         IsChecked="{Binding IsExpanded, 
      RelativeSource={RelativeSource TemplatedParent}}"/> 

所以，如果說我們想（根據您的要求）複製，在相同的模板，我們可以做到這正是但使用不同的名稱。喜歡;

<Style x:Key="{x:Type TreeViewItem}" 
     TargetType="{x:Type TreeViewItem}"> 
    <Setter Property="Background" 
      Value="Transparent" /> 
    <Setter Property="HorizontalContentAlignment" 
      Value="{Binding Path=HorizontalContentAlignment, 
    RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" /> 
    <Setter Property="VerticalContentAlignment" 
      Value="{Binding Path=VerticalContentAlignment, 
    RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" /> 
    <Setter Property="Padding" 
      Value="1,0,0,0" /> 
    <Setter Property="Foreground" 
      Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" /> 
    <Setter Property="FocusVisualStyle" 
      Value="{StaticResource TreeViewItemFocusVisual}" /> 
    <Setter Property="Template"> 
    <Setter.Value> 
     <ControlTemplate TargetType="{x:Type TreeViewItem}"> 
     <Grid> 
      <Grid.ColumnDefinitions> 
      <ColumnDefinition MinWidth="19" 
           Width="Auto" /> 
      <ColumnDefinition Width="Auto" /> 
      <ColumnDefinition Width="*" /> 
      <!-- ** Let's add a column for it ** --> 
      <ColumnDefinition MinWidth="19" Width="Auto"/> 
      </Grid.ColumnDefinitions> 
      <Grid.RowDefinitions> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition /> 
      </Grid.RowDefinitions> 
      <VisualStateManager.VisualStateGroups> 
      <VisualStateGroup x:Name="SelectionStates"> 
       <VisualState x:Name="Selected"> 
       <Storyboard> 
        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd" 
               Storyboard.TargetProperty="(Panel.Background). 
        (SolidColorBrush.Color)" 
               > 
        <EasingColorKeyFrame KeyTime="0" 
             Value="{StaticResource SelectedBackgroundColor}" /> 
        </ColorAnimationUsingKeyFrames> 
       </Storyboard> 
       </VisualState> 
       <VisualState x:Name="Unselected" /> 
       <VisualState x:Name="SelectedInactive"> 
       <Storyboard> 
        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd" 
               Storyboard.TargetProperty="(Panel.Background). 
        (SolidColorBrush.Color)"> 
        <EasingColorKeyFrame KeyTime="0" 
             Value="{StaticResource SelectedUnfocusedColor}" /> 
        </ColorAnimationUsingKeyFrames> 
       </Storyboard> 
       </VisualState> 
      </VisualStateGroup> 
      <VisualStateGroup x:Name="ExpansionStates"> 
       <VisualState x:Name="Expanded"> 
       <Storyboard> 
        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" 
               Storyboard.TargetName="ItemsHost"> 
        <DiscreteObjectKeyFrame KeyTime="0" 
              Value="{x:Static Visibility.Visible}" /> 
        </ObjectAnimationUsingKeyFrames> 
       </Storyboard> 
       </VisualState> 
       <VisualState x:Name="Collapsed" /> 
      </VisualStateGroup> 
      </VisualStateManager.VisualStateGroups> 
      <ToggleButton x:Name="Expander" 
         Style="{StaticResource ExpandCollapseToggleStyle}" 
         ClickMode="Press" 
         IsChecked="{Binding IsExpanded, 
      RelativeSource={RelativeSource TemplatedParent}}"/> 
      <Border x:Name="Bd" 
        Grid.Column="1" 
        Background="{TemplateBinding Background}" 
        BorderBrush="{TemplateBinding BorderBrush}" 
        BorderThickness="{TemplateBinding BorderThickness}" 
        Padding="{TemplateBinding Padding}"> 
      <ContentPresenter x:Name="PART_Header" 
           ContentSource="Header" 
           HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/> 
      </Border> 
      <ItemsPresenter x:Name="ItemsHost" 
          Grid.Row="1" 
          Grid.Column="1" 
          Grid.ColumnSpan="2" 
          Visibility="Collapsed" /> 
      <!-- ** We add a duplicate ToggleButton to act as the expander ** --> 
      <ToggleButton x:Name="Expander2" Grid.Column="3" 
         Style="{StaticResource ExpandCollapseToggleStyle}" 
         ClickMode="Press" 
         IsChecked="{Binding IsExpanded, 
      RelativeSource={RelativeSource TemplatedParent}}"/> 
     </Grid> 
     <ControlTemplate.Triggers> 
      <Trigger Property="HasItems" 
        Value="false"> 
      <Setter TargetName="Expander" 
        Property="Visibility" 
        Value="Hidden" /> 
      </Trigger> 
      <MultiTrigger> 
      <MultiTrigger.Conditions> 
       <Condition Property="HasHeader" 
         Value="false" /> 
       <Condition Property="Width" 
         Value="Auto" /> 
      </MultiTrigger.Conditions> 
      <Setter TargetName="PART_Header" 
        Property="MinWidth" 
        Value="75" /> 
      </MultiTrigger> 
      <MultiTrigger> 
      <MultiTrigger.Conditions> 
       <Condition Property="HasHeader" 
         Value="false" /> 
       <Condition Property="Height" 
         Value="Auto" /> 
      </MultiTrigger.Conditions> 
      <Setter TargetName="PART_Header" 
        Property="MinHeight" 
        Value="19" /> 
      </MultiTrigger> 
     </ControlTemplate.Triggers> 
     </ControlTemplate> 
    </Setter.Value> 
    </Setter> 
</Style> 

主要的是剛剛申請的是ExpandCollapseToggleStyle您切換按鈕，並確保您的ClickMode="Press"這樣你就可以打它。您可以使用您應用的唯一ID複製的控制模板或您的默認值（無論您喜歡什麼）爲您的實例創建特定目錄。

希望這有助於，並歡迎來到SO。歡呼聲:)