Question

我有一个TreeView，其简化定义为

<TreeView ItemsSource="{Binding TreeItems}">
    <TreeView.Resources>
        <DataTemplate DataType="{x:Type models:MyModel}">
            <Border Margin="{Binding Margin}" >
                 <Grid>
                     <TextBlock Text="{Binding Path=Name}" Margin="3,3,3,3" />
                 </Grid>
            </Border>
        </DataTemplate>
    </TreeView.Resources>
</TreeView>

看起来像这样

正如您所看到的，由于边距是可变的，因此项目之间存在空间。问题是下拉箭头。它不以元素为中心。好吧，它集中在忽略边距的元素上。如何调整箭头？

Answer 1

~~您的XAML标记既不完整又不正确：DataTemplate应该是HierarchicalDataTemplate，并且应该放在<TreeView.ItemTemplate>标记中。~~这不是＆＃ 39;在编辑后应用。

您可以将保证金应用于完整的TreeViewItem内容，包括下拉箭头：

<TreeView ItemsSource="{Binding Items}">
    <TreeView.ItemContainerStyle>
        <Style TargetType="TreeViewItem">
            <Setter Property="Margin" Value="{Binding Margin}"/>
        </Style>
    </TreeView.ItemContainerStyle>
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding SubItems}">
            <Border>
                <Grid>
                    <TextBlock Margin="3,3,3,3"/>
                </Grid>
            </Border>    
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

Answer 2

是的，我知道下面的风格太长了，但试一试。只需将其放在单独的资源字典中并合并即可。

<TreeView ItemsSource="{Binding TreeItems}" ItemContainerStyle="{StaticResource CenteredExpanderTreeViewItemStyle}">
    <TreeView.Resources>
        <DataTemplate DataType="{x:Type models:MyModel}">
            <Border Margin="{Binding Margin}" >
                 <Grid>
                     <TextBlock Text="{Binding Path=Name}" Margin="3,3,3,3" />
                 </Grid>
            </Border>
        </DataTemplate>
    </TreeView.Resources>
</TreeView>

CenteredExpanderTreeViewItemStyle.xaml

<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="CenteredExpanderTreeViewItemStyle" 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="Auto"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <ToggleButton x:Name="Expander" VerticalAlignment="Center" 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.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>

Answer 3

使用TreeViewItem的给定样式，如下面的

    Mono<String> m1 = Mono.just("A");
    Mono<String> m2 = Mono.just("B");

    Mono<String> andResult = m1.and(m2).map(t -> t.getT1() + t.getT2());
    Mono<String> whenResult = Mono.when(m1, m2).map(t -> t.getT1() + t.getT2());

希望得到这个帮助。

Answer 4

要为ToggleButton中的TreeView添加保证金，您必须添加自定义ControlTemplate。 MSDN上有几个很好的教程，例如：https://msdn.microsoft.com/de-de/library/ms788727(v=vs.85).aspx

我将一个示例剥离到符合您要求的必要元素。请注意，此示例ToggleButton根本没有样式，因此看起来正常Button会这样做。但我相信，你会找到几个很好的例子来说明如何以最适合你的方式设置这个Button的样式。

代码：

<Window.Resources>
        <Style x:Key="TreeViewItemStyle" TargetType="{x:Type TreeViewItem}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TreeViewItem}">
                        <Grid Margin="{Binding Margin}">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition MinWidth="20" Width="Auto"/>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition Width="*"/>
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"/>
                                <RowDefinition Height="*"></RowDefinition>
                            </Grid.RowDefinitions>
                            <ToggleButton Grid.Column="0" x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" />
                            <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Row="0" 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" Margin="-10,0,0,0"/>
                        </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>
    </Window.Resources>

    <TreeView ItemsSource="{Binding TreeItems}" ItemContainerStyle="{StaticResource TreeViewItemStyle}">
        <TreeView.Resources>
            <HierarchicalDataTemplate DataType="{x:Type library:MyModel}" ItemsSource="{Binding Children}" >
                <TextBlock Text="{Binding Name}"></TextBlock>
            </HierarchicalDataTemplate>
        </TreeView.Resources>
    </TreeView>

Answer 5

你应该能做到这一点：

<Style TargetType="{x:Type TreeViewItem}" BasedOn="{StaticResource {x:Type TreeViewItem}}">
    <Setter Property="Margin" Value="0,0,0,0" />
    <!--Or edit Padding if Margin doesn't work-->
</Style>

它将使用TreeViewItem的默认样式并仅编辑已定义的属性。如果您为TreeViewItem使用明确定义的样式，请使用BaseOn="{StaticResource [YourStyleKey]}"（不带[]）。

如果您需要更高级的样式，我建议您使用Blend来获取ControlTemplate的{{1}}，然后根据您的需要进行编辑，而不会改变太多（保持请记住，用作模板的控件名称可能具有重要意义，因此请注意编辑的内容。

如果您不知道如何使用Blend来获取控件的模板，这里有一个Telerik控件文档中描述的简单教程（不用担心，它的工作方式相同所有控制）。您只需要创建TreeViewItem TreeViewItem的副本，将其粘贴到您的应用程序中即可开始（编辑）。

通过使用Blend，您可以获取TreeView控件的所有构建块的模板，并使它们看起来像您想要的那样。你只需要做一些挖掘。

调整WPF TreeView的下拉箭头边距

5 个答案: