我的datatrigger绑定有什么问题？ [英] What's wrong with my datatrigger binding?

问题描述

我已经创建了一个附加属性来扩展一个带有附加状态的Button类：

I have created an attached property to extend a Button class with additional state:

<Button v:ExtensionHelper.OperationMode="{Binding MyObject.OperationMode}" 
        Command="{Binding MyObject.Select}" 
        Style="{StaticResource operationModeControlTemplateStyle}" />

然后我想在 ControlTemplate 使用 DataTrigger 如下：

<Style x:Key="operationModeControlTemplateStyle" TargetType="Button">
    <Setter Property="IsHitTestVisible" Value="true" />        
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid>
                    <Image x:Name="hand" Source="hand.png" />
                    <Image x:Name="cross" Source="cross.png" />
                </Grid>
                <ControlTemplate.Triggers>
                    <DataTrigger Binding="{Binding Path=(v:ExtensionHelper.OperationMode), RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}" Value="Manual">
                        <Setter TargetName="cross" Property="Visibility" Value="Collapsed" />
                        <Setter TargetName="hand" Property="Visibility" Value="Visible" />
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=(v:ExtensionHelper.OperationMode), RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}" Value="Disabled">
                        <Setter TargetName="cross" Property="Visibility" Value="Visible" />
                        <Setter TargetName="hand" Property="Visibility" Value="Collapsed" />
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=(v:ExtensionHelper.OperationMode), RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}" Value="Automatic">
                        <Setter TargetName="cross" Property="Visibility" Value="Collapsed" />
                        <Setter TargetName="hand" Property="Visibility" Value="Collapsed" />
                    </DataTrigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

但是我收到这个错误：

System.Windows.Data错误：4：不能
查找源代码以引用
'RelativeSource FindAncestor，
AncestorType ='System.Windows.Controls.Button' ，
AncestorLevel ='1''。
BindingExpression：Path =（0）;
DataItem = null; target元素是
'Button'（Name =''）;目标属性是
'NoTarget'（类型'Object'）

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.Button', AncestorLevel='1''. BindingExpression:Path=(0); DataItem=null; target element is 'Button' (Name=''); target property is 'NoTarget' (type 'Object')

DataTrigger 似乎不正确。我做错了什么？

The binding expression in the DataTrigger seems to be incorrect. What am I doing wrong?

推荐答案

答案很简单，如果我花了我的时间阅读文档而不是浪费它发布了一个关于stackoverflow的问题我已经知道：

the answer is pretty simple and if I would have spent my time reading the docs instead of wasting it posting a question on stackoverflow I would already know:

Binding="{Binding RelativeSource={RelativeSource Self}, Path=(v:ExtensionHelper.OperationMode)}"

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