Question

如何在WPF TreeView中隐藏叶节点的展开/合并符号？

换句话说：如何使叶子节点自动扩展？

使用XAML实现此目的的任何方法？

谢谢，

Answer 1

与其他答案类似，要扩展所有节点，您只需使用

即可

<TreeView >
    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded" Value="True" />
        </Style>
    </TreeView.ItemContainerStyle>

这将使所有TreeViewItems自动展开。但是，您仍会看到Expand / Collapse ToggleButton。要摆脱那个，你必须像这样重新模板TreeViewItem

<TreeView ...
          ItemContainerStyle="{StaticResource TreeViewItemExpandedStyle}">

风格（非常Xaml）

<Style x:Key="TreeViewItemExpandedStyle" TargetType="{x:Type TreeViewItem}">
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="IsExpanded" Value="True"/>
    <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="VerticalContentAlignment" Value="{Binding 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="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <ToggleButton x:Name="Expander" IsEnabled="False" Visibility="Hidden" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
                    <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                        <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                    </Border>
                    <ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsExpanded" Value="false">
                        <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="HasItems" Value="false">
                        <Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
                    </Trigger>
                    <Trigger Property="IsSelected" Value="true">
                        <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
                    </Trigger>
                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsSelected" Value="true"/>
                            <Condition Property="IsSelectionActive" Value="false"/>
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                    </MultiTrigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="VirtualizingStackPanel.IsVirtualizing" Value="true">
            <Setter Property="ItemsPanel">
                <Setter.Value>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel/>
                    </ItemsPanelTemplate>
                </Setter.Value>
            </Setter>
        </Trigger>
    </Style.Triggers>
</Style>

<Style x:Key="TreeViewItemFocusVisual">
    <Setter Property="Control.Template">
        <Setter.Value>
            <ControlTemplate>
                <Rectangle/>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>
<PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
<Style x:Key="ExpandCollapseToggleStyle" TargetType="{x:Type ToggleButton}">
    <Setter Property="Focusable" Value="False"/>
    <Setter Property="Width" Value="16"/>
    <Setter Property="Height" Value="16"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ToggleButton}">
                <Border Background="Transparent" Height="16" Padding="5,5,5,5" Width="16">
                    <Path x:Name="ExpandPath" Data="{StaticResource TreeArrow}" Fill="Transparent" Stroke="#FF989898">
                        <Path.RenderTransform>
                            <RotateTransform Angle="135" CenterY="3" CenterX="3"/>
                        </Path.RenderTransform>
                    </Path>
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF1BBBFA"/>
                        <Setter Property="Fill" TargetName="ExpandPath" Value="Transparent"/>
                    </Trigger>
                    <Trigger Property="IsChecked" Value="True">
                        <Setter Property="RenderTransform" TargetName="ExpandPath">
                            <Setter.Value>
                                <RotateTransform Angle="180" CenterY="3" CenterX="3"/>
                            </Setter.Value>
                        </Setter>
                        <Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
                        <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 2

将TreeViewItems绑定到ObservableCollection并将ObservableCollection留空。这样就不会显示展开/折叠标志，因为UI知道没有任何东西可以展开。以下是我的一些代码的相关部分：

XAML：

<TreeView x:Name="TreeView"
    ItemsSource="{Binding TopLevelNodes}" 
    VirtualizingStackPanel.IsVirtualizing="True"
    VirtualizingStackPanel.VirtualizationMode="Recycling">

    <TreeView.Resources>
        <HierarchicalDataTemplate
            DataType="{x:Type local:ViewModel}" ItemsSource="{Binding Children}">

视图模型：

ObservableCollection<ObjectBaseViewModel> _children;

public ObservableCollection<ObjectBaseViewModel> Children
{
    get
    {
        if (_children == null)
            _children = new ObservableCollection<ViewModel>();

        return _children;
    }
}

Answer 3

我不知道纯XAML解决方案，但您可以绑定IsExpanded的{{1}}属性，并且默认情况下将叶节点上的此属性设置为true（您没有在其他节点上完全拥有此属性。

TreeviewItem

Answer 4

首先将IsExpanded设为true

   <Style x:Key="{x:Type TreeViewItem}"
TargetType="{x:Type TreeViewItem}">
<Setter Property="IsExpanded"
    Value="True" />

然后隐藏扩展器

<Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TreeViewItem}">
 <ControlTemplate.Triggers>
     <Trigger Property="HasItems"
         Value="false">
         <Setter TargetName="Expander"
            Property="Visibility"
            Value="Hidden" />
     </Trigger>
     <Trigger Property="HasItems"
              Value="true">
         <Setter TargetName="Expander"
             Property="Visibility"
             Value="Hidden" />
     </Trigger>
                   </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

使用树视图而不是带有rowdetails的数据网格的一个很好的理由是，向上和向下箭头键无缝地从扩展细节遍历到标题细节。

WPF TreeView：隐藏所有叶节点的展开符号

4 个答案: