在 WPF 样式中触发多个条件的正确方法是什么

What's the right way to trigger on multiple conditions in a WPF Style

提问by Tony Vitabile

My WPF application has a DataGridcontrol in it. I have a default custom style for the DataGridRowclass which works well. However, for this one particular DataGridon this one particular screen, I need a different custom style.

我的 WPF 应用程序中有一个DataGrid控件。我有一个默认的自定义样式DataGridRow，效果很好。但是，对于这个DataGrid特定屏幕上的这个特定样式，我需要一种不同的自定义样式。

The Items in each row have a boolproperty that, when set, I want to display that row with a different foreground and background color. However, when the row is selected AND when that property is set, I want a different foreground and background color to show that it's selected AND the property is set to true.

每行中的项目都有一个bool属性，当设置时，我想用不同的前景色和背景色显示该行。However, when the row is selected AND when that property is set, I want a different foreground and background color to show that it's selected AND the property is set to true.

Here's what I've tried:

这是我尝试过的：

<Style TargetType="DataGridRow" x:Key="CameraStyle">
    <Setter Property="Foreground" Value="{DynamicResource TextForeground}" />
    <Setter Property="Background" Value="{DynamicResource DataBackground}" />
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Property="IsSelected" Value="False" />
                <Condition Binding="{Binding Path=IsInLiveMode}" Value="True" />
            </MultiDataTrigger.Conditions>
            <Setter Property="Foreground" Value="Red" />
            <Setter Property="Background" Value="Yellow" />
        </MultiDataTrigger>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Property="IsSelected" Value="True" />
                <Condition Binding="{Binding Path=IsInLiveMode}" Value="True" />
            </MultiDataTrigger.Conditions>
            <Setter Property="Background"  Value="DarkOrange" />
            <Setter Property="BorderBrush" Value="{DynamicResource DataBorder}" />
            <Setter Property="Foreground"  Value="DarkRed" />
        </MultiDataTrigger>
    </Style.Triggers>
</Style>

This gives me a "Binding must be non-null" error, which I think is happening because there is no Bindingproperty on the first condition in the MultiDataTrigger.

这给了我一个“绑定必须为非空”错误，我认为这是因为BindingMultiDataTrigger 中的第一个条件没有属性。

What is the correct way to write this in XAML?

在 XAML 中编写它的正确方法是什么？

EDIT:

编辑：

After trying nemesv's & Rachel's answer, the code now compiles and runs. However, the colors I've chosen for the IsSelected = true and IsInLiveMode = true case are not showing up. Here's what I have now:

在尝试了 nemesv 和 Rachel 的回答之后，代码现在可以编译并运行。但是，我为 IsSelected = true 和 IsInLiveMode = true 案例选择的颜色没有显示。这是我现在所拥有的：

    <Style TargetType="DataGridRow" x:Key="CameraStyle">
        <Setter Property="Background" Value="{DynamicResource DataBackground}" />
        <Setter Property="Foreground" Value="{DynamicResource TextForeground}" />
        <Style.Triggers>
            <MultiDataTrigger>
                <MultiDataTrigger.Conditions>
                    <Condition Binding="{Binding Path=IsSelected, RelativeSource={RelativeSource Self}}" Value="False" />
                    <Condition Binding="{Binding Path=IsInLiveMode}" Value="True" />
                </MultiDataTrigger.Conditions>
                <Setter Property="Background" Value="Yellow" />
                <Setter Property="Foreground" Value="Red" />
            </MultiDataTrigger>
            <MultiDataTrigger>
                <MultiDataTrigger.Conditions>
                    <Condition Binding="{Binding Path=IsSelected, RelativeSource={RelativeSource Self}}" Value="True" />
                    <Condition Binding="{Binding Path=IsInLiveMode}" Value="False" />
                </MultiDataTrigger.Conditions>
                <Setter Property="Background"  Value="{DynamicResource DataBackgroundSelected}" />
                <Setter Property="BorderBrush" Value="{DynamicResource DataBorder}" />
                <Setter Property="Foreground"  Value="{DynamicResource DataForegroundSelected}" />
            </MultiDataTrigger>
            <MultiDataTrigger>
                <MultiDataTrigger.Conditions>
                    <Condition Binding="{Binding Path=IsSelected, RelativeSource={RelativeSource Self}}" Value="True" />
                    <Condition Binding="{Binding Path=IsInLiveMode}" Value="True" />
                </MultiDataTrigger.Conditions>
                <Setter Property="Background"  Value="DarkOrange" />
                <Setter Property="BorderBrush" Value="{DynamicResource DataBorder}" />
                <Setter Property="Foreground"  Value="DarkRed" />
            </MultiDataTrigger>
        </Style.Triggers>
    </Style>

Any ideas on why the case in question isn't working?

关于为什么有问题的案例不起作用的任何想法？

回答by nemesv

Your assumptution is correct regarding the missing binding.

您对缺少绑定的假设是正确的。

From MSDN MultiDataTrigger.Conditions:

从 MSDN MultiDataTrigger.Conditions：

For a MultiDataTrigger, each condition in the collection must set both the Binding and Valueproperties.

对于 MultiDataTrigger，集合中的每个条件都必须设置 Binding 和 Value属性。

You can solve this using RelativeSource Selfto refer yourself in the binding:

您可以使用RelativeSource Self在绑定中引用自己来解决此问题：

<MultiDataTrigger.Conditions>
    <Condition Binding="{Binding RelativeSource={RelativeSource Self},
         Path=IsSelected}" Value="True" />
    <Condition Binding="{Binding Path=IsInLiveMode}" Value="True" />
</MultiDataTrigger.Conditions>

回答by Rachel

You're using a MultiDataTrigger, which is still a DataTriggerand expects a binding

您正在使用 a MultiDataTrigger，它仍然是 aDataTrigger并且需要绑定

Switch Property="IsSelected"in your Conditionto

开关Property="IsSelected"在你Condition来

<Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}" 
           Value="True" />