如何从另一个ControlTemplate使用ControlTemplate？

Question

我有过

<!-- DERIVED1 - DERIVES FROM 'MOST BASE' -->
<ControlTemplate TargetType="ContentControl" x:Key="Derived1WidgetControlTemplate">
    <GroupBox Style="{StaticResource WidgetControlTemplateStyle}">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseLeftButtonDown">
                <i:InvokeCommandAction Command="{Binding ExpandCommand}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>

        <DockPanel>
            <!-- Some additional controls go here ... -->
            <Label Content="Blah blah" />

            <DockPanel>
                <!-- Content ... -->
                <ContentPresenter />
            </DockPanel>
        </DockPanel>
    </GroupBox>
</ControlTemplate>

<!-- MOST BASE -->
<ControlTemplate TargetType="ContentControl" x:Key="WidgetControlTemplate">
    <GroupBox Style="{StaticResource WidgetControlTemplateStyle}">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseLeftButtonDown">
                <i:InvokeCommandAction Command="{Binding ExpandCommand}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>

        <DockPanel>
            <!-- Content ... -->
            <ContentPresenter />
        </DockPanel>
    </GroupBox>
</ControlTemplate>

显然，这两个模板几乎完全相同。我能做些什么来去除重复的片段呢？

将它们合并到单个ControlTemplate中并传递依赖项或附加属性不是一个选项-我需要有两个可区分的控件模板。

Answer 1

与样式不同，您不能仅“覆盖”ControlTemplate的一部分，也不能将ControlTemplate基于另一个ControlTemplate。您必须(重新)将整个模板定义为一个整体。

您可以做的是将GroupBox和模板的所有公共部分移动到UserControl，并将此UserControl包含在两个模板中，例如：

<UserControl x:Class="WpfApplication2.GroupBoxUserControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:WpfApplication2"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Template>
        <ControlTemplate TargetType="UserControl">
            <GroupBox Style="{StaticResource WidgetControlTemplateStyle}">
                <ContentPresenter />
            </GroupBox>
        </ControlTemplate>
    </UserControl.Template>
</UserControl>

...

<ControlTemplate TargetType="ContentControl" x:Key="TemplateA">
    <local:GroupBoxUserControl>
        <TextBlock>1</TextBlock>
    </local:GroupBoxUserControl>
</ControlTemplate>
<ControlTemplate TargetType="ContentControl" x:Key="TemplateB">
    <local:GroupBoxUserControl>
        <TextBlock>2</TextBlock>
    </local:GroupBoxUserControl>
</ControlTemplate>

除此之外，恐怕无法避免在XAML标记中两次声明相同的元素。