WPF：绑定条件与物业，XamlParseException无论是使用 [英] WPF: Condition Binding versus Property, XamlParseException using either

问题描述

我有一个条件麻烦了 MultiTrigger 。如果我做了以下内容：

 ＆lt;条件绑定={绑定的RelativeSource = {的RelativeSource
    AncestorType = {X：类型的ListView}}}属性=IsEnabledVALUE =真/＆GT;
 

然后我得到这个异​​常：

  

条件不能同时使用属性和绑定。在标记文件对象System.Windows.Condition错误

然而，当我做到以下几点：

 ＆lt;条件绑定={绑定的RelativeSource = {的RelativeSource
    AncestorType = {X：类型的ListView}}，路径= IsEnabled}VALUE =真/＆GT;
 

然后我得到这个异​​常：

  

必须指定属性和值的触发。在标记文件对象System.Windows.Condition错误

怎么办？如果它的事项，这里的整个触发：

 ＆LT; MultiTrigger＆GT;
    ＆LT; MultiTrigger.Conditions＆GT;
        ＆lt;条件绑定={绑定路径= IsSelected}VALUE =真/＆GT;
        ＆lt;条件绑定={绑定路径= ItemsControl.AlternationIndex}
                   值=0/＆GT;
        ＆lt;条件绑定={绑定的RelativeSource = {的RelativeSource
            AncestorType = {X：类型的ListView}}，路径= IsEnabled}
                   值=真/＆GT;
    ＆LT; /MultiTrigger.Conditions>
    ＆LT; setter属性=背景
            VALUE ={StaticResource的evenSelected}/＆GT;
    ＆LT; setter属性=BorderBrush
            VALUE ={StaticResource的evenSelectedBorder}/＆GT;
＆LT; / MultiTrigger＆GT;
 

解决方案

在这种情况下，API是混乱的。 条件用于两种不同类型的多触发器，和所使用的特性是不同的。当使用 MultiTrigger ，你会使用属性和值属性。当使用 MultiDataTrigger （这是你所需要的），您可以指定一个绑定和值。所以，如果你只是切换您的code使用 MultiDataTrigger ，你会好走：

 ＆LT; MultiDataTrigger＆GT;
    ＆LT; MultiDataTrigger.Conditions＆GT;
        ＆lt;条件绑定={绑定路径= IsSelected}VALUE =真/＆GT;
        ＆lt;条件绑定={绑定路径= ItemsControl.AlternationIndex}
                   值=0/＆GT;
        ＆lt;条件绑定={绑定的RelativeSource = {的RelativeSource
            AncestorType = {X：类型的ListView}}，路径= IsEnabled}
                   值=真/＆GT;
    ＆LT; /MultiDataTrigger.Conditions>
    ＆LT; setter属性=背景
            VALUE ={StaticResource的evenSelected}/＆GT;
    ＆LT; setter属性=BorderBrush
            VALUE ={StaticResource的evenSelectedBorder}/＆GT;
＆LT; / MultiDataTrigger＆GT;
 

I'm having trouble with a Condition for a MultiTrigger. If I do the following:

<Condition Binding="{Binding RelativeSource={RelativeSource
    AncestorType={x:Type ListView}}}" Property="IsEnabled" Value="True"/>

Then I get this exception:

Condition cannot use both Property and Binding. Error at object 'System.Windows.Condition' in markup file

However, when I do the following:

<Condition Binding="{Binding RelativeSource={RelativeSource
    AncestorType={x:Type ListView}}, Path=IsEnabled}" Value="True"/>

Then I get this exception:

Must specify both Property and Value for Trigger. Error at object 'System.Windows.Condition' in markup file

What gives? If it matters, here's the entire trigger:

<MultiTrigger>
    <MultiTrigger.Conditions>
        <Condition Binding="{Binding Path=IsSelected}" Value="True"/>
        <Condition Binding="{Binding Path=ItemsControl.AlternationIndex}"
                   Value="0"/>
        <Condition Binding="{Binding RelativeSource={RelativeSource
            AncestorType={x:Type ListView}}, Path=IsEnabled}"
                   Value="True"/>
    </MultiTrigger.Conditions>
    <Setter Property="Background"
            Value="{StaticResource evenSelected}" />
    <Setter Property="BorderBrush"
            Value="{StaticResource evenSelectedBorder}" />
</MultiTrigger>

解决方案

The API in this case is confusing. Condition is used for two different types of multi-triggers, and the properties used are different. When using MultiTrigger, you will use the Property and Value properties. When using MultiDataTrigger (which is what you need), you specify a Binding and a Value. So, if you just switch your code to use a MultiDataTrigger, you'll be good to go:

<MultiDataTrigger>
    <MultiDataTrigger.Conditions>
        <Condition Binding="{Binding Path=IsSelected}" Value="True"/>
        <Condition Binding="{Binding Path=ItemsControl.AlternationIndex}"
                   Value="0"/>
        <Condition Binding="{Binding RelativeSource={RelativeSource
            AncestorType={x:Type ListView}}, Path=IsEnabled}"
                   Value="True"/>
    </MultiDataTrigger.Conditions>
    <Setter Property="Background"
            Value="{StaticResource evenSelected}" />
    <Setter Property="BorderBrush"
            Value="{StaticResource evenSelectedBorder}" />
</MultiDataTrigger>

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