展开/折叠时如何使Expander的图标移到边缘

问题描述

展开/折叠时，默认Expander的图标位置是固定的。现在，我需要固定Content的位置的边缘并移动图标。

我尝试过：

<Expander HorizontalAlignment="Left" ExpandDirection="Right" FlowDirection="RightToLeft">
   <Grid>
      <Grid.ColumnDeFinitions>
         <ColumnDeFinition Width="*"></ColumnDeFinition>
      </Grid.ColumnDeFinitions>

      <Grid Grid.Column="0">
         <Grid.ColumnDeFinitions>
            <ColumnDeFinition Width="Auto"></ColumnDeFinition>
            <ColumnDeFinition></ColumnDeFinition>
         </Grid.ColumnDeFinitions>
         <TextBlock Grid.Column="0" Text="123"/>
         <TextBlock Grid.Column="1" Text="abc"/>
      </Grid>
   </Grid>
</Expander>

它接近我想要的，除了我使图标方向向后。这是正确的方法还是解决方法？谢谢。

解决方法

更改流向也会影响控件的其他部分，例如被翻转的图标。而是使用Blend or Visual Studio创建默认控制模板的副本并对其进行调整。

有很多XAML代码被提取出来，但是您只需要适应其中的一小部分即可。仅需要其他样式，因为它们是通过名称静态引用的。将所有这些代码放入您选择的范围内的资源字典中。

<SolidColorBrush x:Key="Expander.Static.Circle.Stroke" Color="#FF333333"/>
<SolidColorBrush x:Key="Expander.Static.Circle.Fill" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="Expander.Static.Arrow.Stroke" Color="#FF333333"/>
<SolidColorBrush x:Key="Expander.MouseOver.Circle.Stroke" Color="#FF5593FF"/>
<SolidColorBrush x:Key="Expander.MouseOver.Circle.Fill" Color="#FFF3F9FF"/>
<SolidColorBrush x:Key="Expander.MouseOver.Arrow.Stroke" Color="#FF000000"/>
<SolidColorBrush x:Key="Expander.Pressed.Circle.Stroke" Color="#FF3C77DD"/>
<SolidColorBrush x:Key="Expander.Pressed.Circle.Fill" Color="#FFD9ECFF"/>
<SolidColorBrush x:Key="Expander.Pressed.Arrow.Stroke" Color="#FF000000"/>
<SolidColorBrush x:Key="Expander.Disabled.Circle.Stroke" Color="#FFBCBCBC"/>
<SolidColorBrush x:Key="Expander.Disabled.Circle.Fill" Color="#FFE6E6E6"/>
<SolidColorBrush x:Key="Expander.Disabled.Arrow.Stroke" Color="#FF707070"/>
<Style x:Key="ExpanderHeaderFocusVisual">
   <Setter Property="Control.Template">
      <Setter.Value>
         <ControlTemplate>
            <Border>
               <Rectangle Margin="0" StrokeDashArray="1 2" SnapsToDevicePixels="true" StrokeThickness="1" Stroke="Black"/>
            </Border>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>
<Style x:Key="ExpanderDownHeaderStyle" TargetType="{x:Type ToggleButton}">
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type ToggleButton}">
            <Border Padding="{TemplateBinding Padding}">
               <Grid Background="Transparent" SnapsToDevicePixels="False">
                  <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="19"/>
                     <ColumnDefinition Width="*"/>
                  </Grid.ColumnDefinitions>
                  <Ellipse x:Name="circle" Fill="{StaticResource Expander.Static.Circle.Fill}" HorizontalAlignment="Center" Height="19" Stroke="{StaticResource Expander.Static.Circle.Stroke}" VerticalAlignment="Center" Width="19"/>
                  <Path x:Name="arrow" Data="M 1,1.5 L 4.5,5 L 8,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="false" StrokeThickness="2" Stroke="{StaticResource Expander.Static.Arrow.Stroke}" VerticalAlignment="Center"/>
                  <ContentPresenter Grid.Column="1" HorizontalAlignment="Left" Margin="4,0" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Center"/>
               </Grid>
            </Border>
            <ControlTemplate.Triggers>
               <Trigger Property="IsChecked" Value="true">
                  <Setter Property="Data" TargetName="arrow" Value="M 1,4.5  L 4.5,1  L 8,4.5"/>
               </Trigger>
               <Trigger Property="IsMouseOver" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.MouseOver.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsPressed" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Stroke}"/>
                  <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Pressed.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsEnabled" Value="false">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Disabled.Arrow.Stroke}"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>
<Style x:Key="ExpanderUpHeaderStyle" TargetType="{x:Type ToggleButton}">
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type ToggleButton}">
            <Border Padding="{TemplateBinding Padding}">
               <Grid Background="Transparent" SnapsToDevicePixels="False">
                  <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="19"/>
                     <ColumnDefinition Width="*"/>
                  </Grid.ColumnDefinitions>
                  <Grid>
                     <Grid.LayoutTransform>
                        <TransformGroup>
                           <TransformGroup.Children>
                              <TransformCollection>
                                 <RotateTransform Angle="180"/>
                              </TransformCollection>
                           </TransformGroup.Children>
                        </TransformGroup>
                     </Grid.LayoutTransform>
                     <Ellipse x:Name="circle" Fill="{StaticResource Expander.Static.Circle.Fill}" HorizontalAlignment="Center" Height="19" Stroke="{StaticResource Expander.Static.Circle.Stroke}" VerticalAlignment="Center" Width="19"/>
                     <Path x:Name="arrow" Data="M 1,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="false" StrokeThickness="2" Stroke="{StaticResource Expander.Static.Arrow.Stroke}" VerticalAlignment="Center"/>
                  </Grid>
                  <ContentPresenter Grid.Column="1" HorizontalAlignment="Left" Margin="4,4.5"/>
               </Trigger>
               <Trigger Property="IsMouseOver" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.MouseOver.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsPressed" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Stroke}"/>
                  <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Pressed.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsEnabled" Value="false">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Disabled.Arrow.Stroke}"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>
<Style x:Key="ExpanderLeftHeaderStyle" TargetType="{x:Type ToggleButton}">
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type ToggleButton}">
            <Border Padding="{TemplateBinding Padding}">
               <Grid Background="Transparent" SnapsToDevicePixels="False">
                  <Grid.RowDefinitions>
                     <RowDefinition Height="19"/>
                     <RowDefinition Height="*"/>
                  </Grid.RowDefinitions>
                  <Grid>
                     <Grid.LayoutTransform>
                        <TransformGroup>
                           <TransformGroup.Children>
                              <TransformCollection>
                                 <RotateTransform Angle="90"/>
                              </TransformCollection>
                           </TransformGroup.Children>
                        </TransformGroup>
                     </Grid.LayoutTransform>
                     <Ellipse x:Name="circle" Fill="{StaticResource Expander.Static.Circle.Fill}" HorizontalAlignment="Center" Height="19" Stroke="{StaticResource Expander.Static.Circle.Stroke}" VerticalAlignment="Center" Width="19"/>
                     <Path x:Name="arrow" Data="M 1,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="false" StrokeThickness="2" Stroke="{StaticResource Expander.Static.Arrow.Stroke}" VerticalAlignment="Center"/>
                  </Grid>
                  <ContentPresenter HorizontalAlignment="Center" Margin="0,4,0" RecognizesAccessKey="True" Grid.Row="1" SnapsToDevicePixels="True" VerticalAlignment="Top"/>
               </Grid>
            </Border>
            <ControlTemplate.Triggers>
               <Trigger Property="IsChecked" Value="true">
                  <Setter Property="Data" TargetName="arrow" Value="M 1,4.5"/>
               </Trigger>
               <Trigger Property="IsMouseOver" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.MouseOver.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsPressed" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Stroke}"/>
                  <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Pressed.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsEnabled" Value="false">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Disabled.Arrow.Stroke}"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>
<Style x:Key="ExpanderRightHeaderStyle" TargetType="{x:Type ToggleButton}">
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type ToggleButton}">
            <Border Padding="{TemplateBinding Padding}">
               <Grid Background="Transparent" SnapsToDevicePixels="False">
                  <Grid.RowDefinitions>
                     <RowDefinition Height="19"/>
                     <RowDefinition Height="*"/>
                  </Grid.RowDefinitions>
                  <Grid>
                     <Grid.LayoutTransform>
                        <TransformGroup>
                           <TransformGroup.Children>
                              <TransformCollection>
                                 <RotateTransform Angle="-90"/>
                              </TransformCollection>
                           </TransformGroup.Children>
                        </TransformGroup>
                     </Grid.LayoutTransform>
                     <Ellipse x:Name="circle" Fill="{StaticResource Expander.Static.Circle.Fill}" HorizontalAlignment="Center" Height="19" Stroke="{StaticResource Expander.Static.Circle.Stroke}" VerticalAlignment="Center" Width="19"/>
                     <Path x:Name="arrow" Data="M 1,4.5"/>
               </Trigger>
               <Trigger Property="IsMouseOver" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.MouseOver.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.MouseOver.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsPressed" Value="true">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Stroke}"/>
                  <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Pressed.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Pressed.Arrow.Stroke}"/>
               </Trigger>
               <Trigger Property="IsEnabled" Value="false">
                  <Setter Property="Stroke" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Stroke}"/>
                  <Setter Property="Fill" TargetName="circle" Value="{StaticResource Expander.Disabled.Circle.Fill}"/>
                  <Setter Property="Stroke" TargetName="arrow" Value="{StaticResource Expander.Disabled.Arrow.Stroke}"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>

<!-- This is the style that actually needs to be adapted. -->
<Style x:Key="ExpanderStyle" TargetType="{x:Type Expander}">
   <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
   <Setter Property="Background" Value="Transparent"/>
   <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
   <Setter Property="VerticalContentAlignment" Value="Stretch"/>
   <Setter Property="BorderBrush" Value="Transparent"/>
   <Setter Property="BorderThickness" Value="1"/>
   <Setter Property="Template">
      <Setter.Value>
         <ControlTemplate TargetType="{x:Type Expander}">
            <Border Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" CornerRadius="3" SnapsToDevicePixels="true">
               <DockPanel>
                  <ToggleButton x:Name="HeaderSite" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}" DockPanel.Dock="Bottom" FontStyle="{TemplateBinding FontStyle}" FontStretch="{TemplateBinding FontStretch}" FontWeight="{TemplateBinding FontWeight}" FocusVisualStyle="{StaticResource ExpanderHeaderFocusVisual}" FontFamily="{TemplateBinding FontFamily}" Foreground="{TemplateBinding Foreground}" FontSize="{TemplateBinding FontSize}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsChecked="{Binding IsExpanded,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" MinHeight="0" MinWidth="0" Margin="1" Padding="{TemplateBinding Padding}" Style="{StaticResource ExpanderDownHeaderStyle}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                  <ContentPresenter x:Name="ExpandSite" DockPanel.Dock="Top" Focusable="false" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Visibility="Collapsed"/>
               </DockPanel>
            </Border>
            <ControlTemplate.Triggers>
               <Trigger Property="IsExpanded" Value="true">
                  <Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
               </Trigger>
               <Trigger Property="ExpandDirection" Value="Right">
                  <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Left"/>
                  <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Right"/>
                  <Setter Property="Style" TargetName="HeaderSite" Value="{StaticResource ExpanderRightHeaderStyle}"/>
               </Trigger>
               <Trigger Property="ExpandDirection" Value="Up">
                  <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Bottom"/>
                  <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Top"/>
                  <Setter Property="Style" TargetName="HeaderSite" Value="{StaticResource ExpanderUpHeaderStyle}"/>
               </Trigger>
               <Trigger Property="ExpandDirection" Value="Left">
                  <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Right"/>
                  <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Left"/>
                  <Setter Property="Style" TargetName="HeaderSite" Value="{StaticResource ExpanderLeftHeaderStyle}"/>
               </Trigger>
               <Trigger Property="IsEnabled" Value="false">
                  <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
               </Trigger>
            </ControlTemplate.Triggers>
         </ControlTemplate>
      </Setter.Value>
   </Setter>
</Style>

唯一的更改是上一个样式ExpanderStyle。有一个DockPanel，其中包含图标和标题，它们显示在ToggleButton中，内容显示在ContentPresenter中。我只是翻转了这些控件和触发器中的DockPanel.Dock值。

您可以在不设置流向的情况下应用这种样式。

<Expander Style="{StaticResource ExpanderStyle}" HorizontalAlignment="Left" ExpandDirection="Right">