首页 > 解决方案 > WPF TreeViewItem 水平对齐

问题描述

我正在使用 WPF 4.5.2

我的基本结构是这样的

<UserControl>
    <Grid>
        <ContentPresenter />            
    </Grid>
</UserControl>

例如,在运行时 ContentPresenter 托管一个 TreeView

<TreeView>
    <TreeViewItem Header="Node 1">
        <TreeViewItem Header="Leaf 1" />
        <TreeViewItem Header="Leaf 2" />
    </TreeViewItem>
    <TreeViewItem Header="Node 2" />
</TreeView> 

我想要标题为 Node 的 TreeViewItems。被拉伸到父 UserControl 的宽度。

不幸的是,TreeView 本身被拉伸到应用程序窗口的宽度。

如何在节点项的样式中设置宽度?

提前致谢!

标签: wpfalignmentelement-binding

解决方案


如果要拉伸 a TreeViewItem,则必须将其默认值复制ControlTemplate到 XAML 中并根据您的要求对其进行编辑。

这是一堆 XAML,但恐怕没有任何属性或任何东西可以设置来完成此操作而无需定义自定义模板:

<TreeView>
    <TreeView.Resources>
        <Style x:Key="TreeViewItemFocusVisual">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Rectangle/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF27C7F7"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="#FFCCEEFB"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF1CC4F7"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF82DFFB"/>
        <PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF818181"/>
        <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="{StaticResource TreeViewItem.TreeArrow.Static.Fill}" Stroke="{StaticResource TreeViewItem.TreeArrow.Static.Stroke}">
                                <Path.RenderTransform>
                                    <RotateTransform Angle="135" CenterY="3" CenterX="3"/>
                                </Path.RenderTransform>
                            </Path>
                        </Border>
                        <ControlTemplate.Triggers>
                            <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="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Fill}"/>
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Stroke}"/>
                            </Trigger>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Stroke}"/>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Fill}"/>
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsMouseOver" Value="True"/>
                                    <Condition Property="IsChecked" Value="True"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Stroke}"/>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Fill}"/>
                            </MultiTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style x:Key="StretchingTreeViewItemStyle" TargetType="{x:Type TreeViewItem}">
            <Setter Property="Background" Value="Transparent"/>
            <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="*"/>
                                <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"
                                            Grid.ColumnSpan="2">
                                <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.InactiveSelectionHighlightBrushKey}}"/>
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"/>
                            </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="VirtualizingPanel.IsVirtualizing" Value="true">
                    <Setter Property="ItemsPanel">
                        <Setter.Value>
                            <ItemsPanelTemplate>
                                <VirtualizingStackPanel/>
                            </ItemsPanelTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </TreeView.Resources>
    <TreeViewItem Header="Node 1" Style="{StaticResource StretchingTreeViewItemStyle}">
        <TreeViewItem Header="Leaf 1" />
        <TreeViewItem Header="Leaf 2" />
    </TreeViewItem>
    <TreeViewItem Header="Node 2" Style="{StaticResource StretchingTreeViewItemStyle}" />
</TreeView>

推荐阅读