如何在单击标题时阻止WPF Expander扩展？我希望我的Expander仅在单击展开按钮时展开或折叠。
我认为答案与取消泡沫事件有关。如果可能的话，我想在XAML中实现解决方案，同时避免重新模拟整个Expander。
答案 0 :(得分：16)
实际上，比修改模板更简单的XAML解决方案。在这种情况下，不要使用Expander的头属性。而是使用您自己的样式TextBlock覆盖扩展器。
<Application.Resources>
<Style x:Key="ExpanderHeader" TargetType="{x:Type TextBlock}">
<Setter Property="Height" Value="22" />
<Setter Property="Margin" Value="21,0,0,0" />
<Setter Property="Padding" Value="9,3,0,0" />
<Setter Property="HorizontalAlignment" Value="Stretch" />
<Setter Property="VerticalAlignment" Value="Top" />
</Style>
</Application.Resources>
<Grid>
<Expander>
<TextBlock Text="I am some content. I have disowned my default header." Margin="10,5" />
</Expander>
<TextBlock Text="I'm filling in for the default header. You'll like me better anyway."
Style="{StaticResource ResourceKey=ExpanderHeader}"/>
</Grid>
答案 1 :(得分：4)
标题是创建事件的按钮，因此您需要更改Expander的模板，只需将扩展器图标作为按钮。
以下是how to change the expander的帖子。
答案 2 :(得分：2)
我的解决方案是将标题留空并仅标记在作为标题的控件上（使用画布进行绝对定位），这样只有图标会扩展控件：
<Grid Height="{Binding ElementName=exp, Path=ActualHeight}">
<Canvas>
<Expander Name="exp">
...
</Expander>
<Control Style="{StaticResource ExpanderHeaderStyle}" Margin="20,0,0,0" />
</Canvas>
</Grid>
答案 3 :(得分：1)
我按照Simeon的建议修改了Expander控件的默认模板。
以下ControlTemplate定义了一个扩展器，它只在用户点击标题图标时作出反应（扩展/折叠）。
这很快又很脏，所以希望它会破裂。
<ControlTemplate x:Key="LazyExpanderTemplate" TargetType="Expander">
<Border BorderThickness="{TemplateBinding Border.BorderThickness}" CornerRadius="3,3,3,3" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" SnapsToDevicePixels="True">
<DockPanel>
<DockPanel DockPanel.Dock="Top" Name="HeaderSite">
<ToggleButton
DockPanel.Dock="Left"
IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsExpanded}"
Foreground="{TemplateBinding TextElement.Foreground}"
FontFamily="{TemplateBinding TextElement.FontFamily}"
FontSize="{TemplateBinding TextElement.FontSize}"
FontStretch="{TemplateBinding TextElement.FontStretch}"
FontStyle="{TemplateBinding TextElement.FontStyle}"
FontWeight="{TemplateBinding TextElement.FontWeight}"
HorizontalContentAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
VerticalContentAlignment="{TemplateBinding Control.VerticalContentAlignment}"
Padding="{TemplateBinding Control.Padding}"
MinWidth="0"
MinHeight="0"
Margin="1,1,1,1"
>
<ToggleButton.Style>
<Style TargetType="ToggleButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="{TemplateBinding Control.Padding}">
<Grid Background="#00FFFFFF" SnapsToDevicePixels="False">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="19" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Ellipse Stroke="#FFA9A9A9" Name="circle" Width="19" Height="19" HorizontalAlignment="Center" VerticalAlignment="Center" />
<Ellipse Name="shadow" Width="17" Height="17" HorizontalAlignment="Center" VerticalAlignment="Center" Visibility="Hidden" />
<Path Data="M1,1.5L4.5,5 8,1.5" Stroke="#FF666666" StrokeThickness="2" Name="arrow" HorizontalAlignment="Center" VerticalAlignment="Center" SnapsToDevicePixels="False" />
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked" Value="True" >
<Setter Property="Path.Data" TargetName="arrow">
<Setter.Value>
<StreamGeometry>M1,4.5L4.5,1 8,4.5</StreamGeometry>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="UIElement.IsMouseOver" Value="True">
<Setter Property="Shape.Stroke" TargetName="circle">
<Setter.Value>
<SolidColorBrush>#FF666666</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Stroke" TargetName="arrow">
<Setter.Value>
<SolidColorBrush>#FF222222</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="UIElement.Visibility" TargetName="shadow">
<Setter.Value>
<x:Static Member="Visibility.Visible" />
</Setter.Value>
</Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
<ToggleButton.FocusVisualStyle>
<Style TargetType="IFrameworkInputElement">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Border>
<Rectangle Stroke="#FF000000" StrokeThickness="1" StrokeDashArray="1 2" Margin="0,0,0,0" SnapsToDevicePixels="True" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.FocusVisualStyle>
</ToggleButton>
<ContentPresenter
RecognizesAccessKey="True"
Content="{TemplateBinding HeaderedContentControl.Header}"
ContentTemplate="{TemplateBinding HeaderedContentControl.HeaderTemplate}"
ContentStringFormat="{TemplateBinding HeaderedContentControl.HeaderStringFormat}"
Margin="4,0,0,0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
SnapsToDevicePixels="True"
/>
</DockPanel>
<ContentPresenter Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Name="ExpandSite" Margin="{TemplateBinding Control.Padding}" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" Visibility="Collapsed" Focusable="False" DockPanel.Dock="Bottom" />
</DockPanel>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="Expander.IsExpanded">
<Setter Property="UIElement.Visibility" TargetName="ExpandSite">
<Setter.Value>
<x:Static Member="Visibility.Visible" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="Expander.ExpandDirection" Value="Right">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Right"/>
<Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Left"/>
<Setter Property="FrameworkElement.Style" TargetName="HeaderSite">
<Setter.Value>
<Style TargetType="ToggleButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="{TemplateBinding Control.Padding}">
<Grid Background="#00FFFFFF" SnapsToDevicePixels="False">
<Grid.RowDefinitions>
<RowDefinition Height="19" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid>
<Grid.LayoutTransform>
<TransformGroup>
<TransformGroup.Children>
<RotateTransform Angle="-90" />
</TransformGroup.Children>
</TransformGroup>
</Grid.LayoutTransform>
<Ellipse Stroke="#FFA9A9A9" Name="circle" Width="19" Height="19" HorizontalAlignment="Center" VerticalAlignment="Center" />
<Ellipse Name="shadow" Width="17" Height="17" HorizontalAlignment="Center" VerticalAlignment="Center" Visibility="Hidden" />
<Path Data="M1,1.5L4.5,5 8,1.5" Stroke="#FF666666" StrokeThickness="2" Name="arrow" HorizontalAlignment="Center" VerticalAlignment="Center" SnapsToDevicePixels="False" />
</Grid>
<ContentPresenter RecognizesAccessKey="True" Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Margin="0,4,0,0" HorizontalAlignment="Center" VerticalAlignment="Top" SnapsToDevicePixels="True" Grid.Row="1" />
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked">
<Setter Property="Path.Data" TargetName="arrow">
<Setter.Value>
<StreamGeometry>M1,4.5L4.5,1 8,4.5</StreamGeometry>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="UIElement.IsMouseOver">
<Setter Property="Shape.Stroke" TargetName="circle">
<Setter.Value>
<SolidColorBrush>#FF666666</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Stroke" TargetName="arrow">
<Setter.Value>
<SolidColorBrush>#FF222222</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="UIElement.Visibility" TargetName="shadow">
<Setter.Value>
<x:Static Member="Visibility.Visible" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="Expander.ExpandDirection">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Top"/>
<Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Bottom"/>
<Setter Property="FrameworkElement.Style" TargetName="HeaderSite">
<Setter.Value>
<Style TargetType="ToggleButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="{TemplateBinding Control.Padding}">
<Grid Background="#00FFFFFF" SnapsToDevicePixels="False">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="19" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid>
<Grid.LayoutTransform>
<TransformGroup>
<TransformGroup.Children>
<RotateTransform Angle="180" />
</TransformGroup.Children>
</TransformGroup>
</Grid.LayoutTransform>
<Ellipse Stroke="#FFA9A9A9" Name="circle" Width="19" Height="19" HorizontalAlignment="Center" VerticalAlignment="Center" />
<Ellipse Name="shadow" Width="17" Height="17" HorizontalAlignment="Center" VerticalAlignment="Center" Visibility="Hidden" />
<Path Data="M1,1.5L4.5,5 8,1.5" Stroke="#FF666666" StrokeThickness="2" Name="arrow" HorizontalAlignment="Center" VerticalAlignment="Center" SnapsToDevicePixels="False" />
</Grid>
<ContentPresenter RecognizesAccessKey="True" Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Margin="4,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" SnapsToDevicePixels="True" Grid.Column="1" />
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked">
<Setter Property="Path.Data" TargetName="arrow">
<Setter.Value>
<StreamGeometry>M1,4.5L4.5,1 8,4.5</StreamGeometry>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="UIElement.IsMouseOver">
<Setter Property="Shape.Stroke" TargetName="circle">
<Setter.Value>
<SolidColorBrush>#FF666666</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Stroke" TargetName="arrow">
<Setter.Value>
<SolidColorBrush>#FF222222</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="UIElement.Visibility" TargetName="shadow">
<Setter.Value>
<x:Static Member="Visibility.Visible" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
<Trigger.Value>
<x:Static Member="ExpandDirection.Up" />
</Trigger.Value>
</Trigger>
<Trigger Property="Expander.ExpandDirection">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite">
<Setter.Value>
<x:Static Member="Dock.Left" />
</Setter.Value>
</Setter>
<Setter Property="DockPanel.Dock" TargetName="HeaderSite">
<Setter.Value>
<x:Static Member="Dock.Right" />
</Setter.Value>
</Setter>
<Setter Property="FrameworkElement.Style" TargetName="HeaderSite">
<Setter.Value>
<Style TargetType="ToggleButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Border Padding="{TemplateBinding Control.Padding}">
<Grid Background="#00FFFFFF" SnapsToDevicePixels="False">
<Grid.RowDefinitions>
<RowDefinition Height="19" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid>
<Grid.LayoutTransform>
<TransformGroup>
<TransformGroup.Children>
<RotateTransform Angle="90" />
</TransformGroup.Children>
</TransformGroup>
</Grid.LayoutTransform>
<Ellipse Stroke="#FFA9A9A9" Name="circle" Width="19" Height="19" HorizontalAlignment="Center" VerticalAlignment="Center" />
<Ellipse Name="shadow" Width="17" Height="17" HorizontalAlignment="Center" VerticalAlignment="Center" Visibility="Hidden" />
<Path Data="M1,1.5L4.5,5 8,1.5" Stroke="#FF666666" StrokeThickness="2" Name="arrow" HorizontalAlignment="Center" VerticalAlignment="Center" SnapsToDevicePixels="False" />
</Grid>
<ContentPresenter RecognizesAccessKey="True" Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Margin="0,4,0,0" HorizontalAlignment="Center" VerticalAlignment="Top" SnapsToDevicePixels="True" Grid.Row="1" />
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked">
<Setter Property="Path.Data" TargetName="arrow">
<Setter.Value>
<StreamGeometry>M1,4.5L4.5,1 8,4.5</StreamGeometry>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="UIElement.IsMouseOver">
<Setter Property="Shape.Stroke" TargetName="circle">
<Setter.Value>
<SolidColorBrush>#FF666666</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="Shape.Stroke" TargetName="arrow">
<Setter.Value>
<SolidColorBrush>#FF222222</SolidColorBrush>
</Setter.Value>
</Setter>
<Setter Property="UIElement.Visibility" TargetName="shadow">
<Setter.Value>
<x:Static Member="Visibility.Visible" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
<Trigger.Value>
<x:Static Member="ExpandDirection.Left" />
</Trigger.Value>
</Trigger>
<Trigger Property="UIElement.IsEnabled">
<Setter Property="TextElement.Foreground">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.GrayTextBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>False</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
答案 4 :(得分：1)
一个相当简单的解决方案是按以下方式修改Expander控件tempate使用的切换按钮模板。
将内容展示者IsHitTestVisible设置为False
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border Padding="{TemplateBinding Padding}" Background="{x:Null}">
<Grid Background="{x:Null}" 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" HorizontalAlignment="Center" Height="19" Stroke="DarkGray" 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" Stroke="#666" StrokeThickness="2" VerticalAlignment="Center"/>
</Grid>
<ContentPresenter HorizontalAlignment="Center" Margin="0,4,0,0" Grid.Row="1" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Top"IsHitTestVisible="False"/>
</Grid>
</Border>
</ControlTemplate>
答案 5 :(得分：0)
您可以将IsEnabled设置为false，但是如果您需要确定在单击标题时是否可以展开或折叠：
public class MyExpander : Expander
{
private bool CanExpand() => true;
private bool CanCollapse() => true;
private bool rollback;
protected override void OnExpanded()
{
if (rollback) return;
if (CanExpand())
{
base.OnExpanded();
}
else
{
rollback = true;
SetCurrentValue(IsExpandedProperty, false);
rollback = false;
}
}
protected override void OnCollapsed()
{
if (rollback) return;
if (CanCollapse())
{
base.OnCollapsed();
}
else
{
rollback = true;
SetCurrentValue(IsExpandedProperty, true);
rollback = false;
}
}
}
答案 6 :(得分：0)
正如我刚刚检查过的，标题被命名为“ HeaderSite”。您可以使用类似描述的in this post的方法来按名称查找子级。当您有了孩子时，您只需更改其可见性即可。还要确保已加载扩展器，否则您将看不到孩子。
expander.Loaded += (s, e) => {
var hv = expander.findChildByName("HeaderSite");
if (hv == null) return;
hv.Visibility = Visibility.Collapsed;
};
我想这不能保证名称不会更改，对我来说，这只是表面上的问题。