用于向右展开（WPF）展开项目的按钮

Question

默认情况下，扩展器是这样的：

但是我想像下面的图像那样将项目向右扩展的按钮：（我真的不知道该项目是否称为按钮）

欢迎任何建议或评论。

Answer 1

您可以通过编辑ToggleButton的模板将按钮向右移动。这是一个完整的工作示例，可以根据您的要求进行复制，粘贴和编辑：

<Expander Header="Header...">
    <Expander.Template>
        <ControlTemplate TargetType="{x:Type Expander}">
            <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="3" SnapsToDevicePixels="true">
                <DockPanel>
                    <ToggleButton x:Name="HeaderSite" ContentTemplate="{TemplateBinding HeaderTemplate}" 
                                          ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}" 
                                          Content="{TemplateBinding Header}" 
                                          DockPanel.Dock="Top" 
                                          Foreground="{TemplateBinding Foreground}" 
                                          FontWeight="{TemplateBinding FontWeight}" 
                                          FontStyle="{TemplateBinding FontStyle}" 
                                          FontStretch="{TemplateBinding FontStretch}" 
                                          FontSize="{TemplateBinding FontSize}" FontFamily="{TemplateBinding FontFamily}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" MinWidth="0" MinHeight="0" Padding="{TemplateBinding Padding}" 
                                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
                        <ToggleButton.Style>
                            <Style TargetType="{x:Type ToggleButton}">
                                <Style.Resources>
                                    <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"/>
                                    <SolidColorBrush x:Key="Expander.Static.Circle.Fill" Color="#FFFFFFFF"/>
                                    <SolidColorBrush x:Key="Expander.Static.Circle.Stroke" Color="#FF333333"/>
                                    <SolidColorBrush x:Key="Expander.Static.Arrow.Stroke" Color="#FF333333"/>
                                </Style.Resources>
                                <Setter Property="Template">
                                    <Setter.Value>
                                        <ControlTemplate TargetType="{x:Type ToggleButton}">
                                            <Border Padding="{TemplateBinding Padding}">
                                                <Grid Background="Transparent" SnapsToDevicePixels="False">
                                                    <Grid.ColumnDefinitions>
                                                        <ColumnDefinition Width="*"/>
                                                        <ColumnDefinition Width="19"/>
                                                    </Grid.ColumnDefinitions>
                                                    <Ellipse Grid.Column="1" x:Name="circle" Fill="{StaticResource Expander.Static.Circle.Fill}" HorizontalAlignment="Center" Height="19" Stroke="{StaticResource Expander.Static.Circle.Stroke}" VerticalAlignment="Center" Width="19"/>
                                                    <Path Grid.Column="1" x:Name="arrow" Data="M 1,1.5 L 4.5,5 L 8,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="false" Stroke="{StaticResource Expander.Static.Arrow.Stroke}" StrokeThickness="2" VerticalAlignment="Center"/>
                                                    <ContentPresenter HorizontalAlignment="Left" Margin="0,0,4,0" 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>
                        </ToggleButton.Style>
                    </ToggleButton>
                    <ContentPresenter x:Name="ExpandSite" DockPanel.Dock="Bottom" Focusable="false" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                </DockPanel>
            </Border>
            <ControlTemplate.Triggers>
                <Trigger Property="IsExpanded" Value="true">
                    <Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
                </Trigger>
                <Trigger Property="IsEnabled" Value="false">
                    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
    </Expander.Template>
</Expander>