具有右对齐值的 WPF TreeView

Question

我的 wpf 树视图有问题。它的代码是这样的：

<TreeView ItemsSource="{Binding Path=Items}" Grid.RowSpan="2" Grid.ColumnSpan="2">
        <TreeView.Resources>
            <HierarchicalDataTemplate DataType="{x:Type m:MyTreeItem}" ItemsSource="{Binding Items}">
                <DockPanel LastChildFill="True">
                    <TextBlock Text="{Binding Path=Value}" DockPanel.Dock="Right"/>
                    <TextBlock Text="{Binding Path=Display}" DockPanel.Dock="Left"/>
                </DockPanel>
            </HierarchicalDataTemplate>
        </TreeView.Resources>
    </TreeView>

其中 MyTreeItem 是一个简单的类，具有 2 个字符串属性（显示和值）和一个名为 Items 的 MyTreeItem 列表。

我需要树视图来显示所有向右对齐的“值”，同时根据深度维护项目“显示”的树列表。

我尝试将dockPanel设置为固定宽度，但没有成功。

我想在没有任何 c# 代码的情况下执行此操作，只需 xaml。

提前致谢。

Answer 1

如果我正确理解您的问题，您想拉伸TreeViewItems 并将Value 向右对齐。要使TreeViewItems 横向拉伸，您需要编辑TreeViewItem 的模板。问题在这里解释：http://leecampbell.blogspot.com/2009/01/horizontal-stretch-on-treeviewitems.html

这是TreeViewItem 的编辑版本，它执行此操作。请注意，您必须添加对 PresentationFramework.Aero 的引用才能使其工作

示例

<TreeView ItemsSource="{Binding Path=Items}"
            Grid.RowSpan="2"
            Grid.ColumnSpan="2"
            ItemContainerStyle="{StaticResource StretchTreeViewItemStyle}">
    <TreeView.Resources>
        <HierarchicalDataTemplate DataType="{x:Type m:MyTreeItem}" ItemsSource="{Binding Items}">
            <DockPanel LastChildFill="True">
                <TextBlock Text="{Binding Path=Value}" DockPanel.Dock="Right"/>
                <TextBlock Text="{Binding Path=Display}" DockPanel.Dock="Left"/>
            </DockPanel>
        </HierarchicalDataTemplate>
    </TreeView.Resources>
</TreeView>

StretchTreeViewItemStyle

<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>
<Style x:Key="StretchTreeViewItemStyle"
    TargetType="{x:Type TreeViewItem}"
    xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero">
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
    <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="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <ToggleButton x:Name="Expander" 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.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>

Answer 2

class StretchedTreeView : TreeView {
    protected override void OnItemContainerStyleChanged(Style oldItemContainerStyle, Style newItemContainerStyle) {
        base.OnItemContainerStyleChanged(oldItemContainerStyle, newItemContainerStyle);
        newItemContainerStyle.Setters
            .Add(new EventSetter(LoadedEvent, new RoutedEventHandler(TreeViewItem_Loaded)));
    }
    void TreeViewItem_Loaded(object sender, RoutedEventArgs e) {
        TreeViewItem item = sender as TreeViewItem;
        if (item == null) {
            return;
        }
        ContentPresenter cp = FindVisualChild<ContentPresenter>(item);
        cp.HorizontalAlignment = HorizontalAlignment.Stretch;
        Border border = FindVisualChild<Border>(item, "Bd");
        border.SetValue(Grid.ColumnSpanProperty, 2);
    }
    static T FindVisualChild<T>(DependencyObject obj, string name = null) where T : DependencyObject {
        for (int i = 0 ; i < VisualTreeHelper.GetChildrenCount(obj) ; i++) {
            DependencyObject child = VisualTreeHelper.GetChild(obj, i);
            if (child != null && child is T
                && (name == null || !(child is FrameworkElement) || name == ((FrameworkElement) child).Name)) {
                return (T) child;
            }
            else {
                T childOfChild = FindVisualChild<T>(child, name);
                if (childOfChild != null) {
                    return childOfChild;
                }
            }
        }
        return null;
    }
}