C# 如何获得触发器以根据 DataContext 属性更改 TextBlock 的颜色？
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How can I get a trigger to change the color of a TextBlock based on a DataContext Property?
提问by Edward Tanguay
Why does the following code get the runtime error:
为什么以下代码会出现运行时错误：
Members of the Triggers collection must be of type EventTrigger
Triggers 集合的成员必须是 EventTrigger 类型
But the EventTrigger element doesn't have a Binding property.
但是 EventTrigger 元素没有 Binding 属性。
So how do I change the color of the TextBlock based on the DataContext Property?
那么如何根据 DataContext 属性更改 TextBlock 的颜色呢？
XAML:
XAML：
<Window x:Class="TestTrigger123345.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<StackPanel HorizontalAlignment="Left">
<TextBlock Text="{Binding Status}">
<TextBlock.Triggers>
<DataTrigger Binding="{Binding Status}" Value="off">
<Setter Property="TextBlock.Background" Value="Red"/>
</DataTrigger>
</TextBlock.Triggers>
</TextBlock>
</StackPanel>
</Window>
Code:
代码：
namespace TestTriggers
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
DataContext = this;
Status = "off";
}
public string Status { get; set; }
}
}
采纳答案by Arcturus
That is because you can only set event triggers directly on the Trigger property..
那是因为您只能直接在 Trigger 属性上设置事件触发器。
Use a style to achieve what you want:
使用样式来实现您想要的：
<Style x:Key="Triggers" TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding Status}" Value="off">
<Setter Property="TextBlock.Background" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
The following objects have Triggers collections that can contain the trigger types listed:
以下对象具有可以包含列出的触发器类型的 Triggers 集合：
FrameworkElement Style, ControlTemplate, DataTemplate
---------------- ------------------------------------
EventTrigger EventTrigger
Trigger or MultiTrigger
DataTrigger or MultiDataTrigger
回答by Matt Hamilton
You can do it in a style:
你可以用一种风格来做：
<TextBlock Text="{Binding Status}">
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding Status}" Value="off">
<Setter Property="Background" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
回答by paparazzo
There is a typo as you did not close out Style.Triggers. And I found I needed to use the property TextBlock.Background. Thanks, you got me to the solution.
有一个错字，因为您没有关闭 Style.Triggers。我发现我需要使用属性 TextBlock.Background。谢谢，你让我找到了解决方案。
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding Status}" Value="off">
<Setter Property="TextBlock.Background" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
