DataTrigger不会更改Text属性

我正在尝试对样式使用数据触发来更改属性。

I'm attempting to use a data-trigger on a style to change a property.

符合 最小，完整和可验证的示例的要求...

要重现，请首先在Visual Studio中创建一个WPF应用程序。

To reproduce, first create a WPF application in Visual Studio.

在App.xaml中.cs：

Within the App.xaml.cs :

using System.ComponentModel;
using System.Windows;

namespace Foo{
/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application, INotifyPropertyChanged {
        private bool _clicked;
        public bool Clicked {
            get { return this._clicked; }
            set {
                this._clicked = value;
                this.PropertyChanged?.Invoke(
                    this, new PropertyChangedEventArgs( "Clicked" ) );
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }
}

在MainWindow.xaml中：

Within the MainWindow.xaml :

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:lib="clr-namespace:System;assembly=mscorlib"
    xmlns:local="clr-namespace:Foo"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    mc:Ignorable="d" x:Class="Foo.MainWindow"
    Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <lib:Boolean x:Key="True">True</lib:Boolean>
    </Window.Resources>
    <Grid>
        <Button x:Name="button" Click="button_Click">
            <Viewbox>
                <TextBlock Text="Unclicked">
                    <TextBlock.Style>
                        <Style TargetType="{x:Type TextBlock}">
                            <Style.Triggers>
                                <DataTrigger
                                        Binding="{Binding
                                            Clicked,
                                            Source={x:Static Application.Current}}"
                                            Value="{StaticResource True}">
                                    <Setter Property="Text" Value="Clicked" />
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </TextBlock.Style>
                </TextBlock>
            </Viewbox>
        </Button>
    </Grid>
</Window>

在MainWindow.xaml.cs中-

Within the MainWindow.xaml.cs -

using System.Windows;

namespace Foo{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window {
        public MainWindow( ) {
            InitializeComponent( );
        }

        private void button_Click( object sender, RoutedEventArgs e ) {
            ( Application.Current as App ).Clicked = !( Application.Current as App ).Clicked;
        }
    }
}

作为旁注-我尝试将数据触发器的值设置为 True ，但这也不起作用（触发器未捕获，并且基于设置该属性的文本也未更改到一个新值）。

As a side note - I tried setting the value of the data trigger to just "True", and that also did not work ( the trigger did not catch, and text did not change based on setting the property to a new value ).

那么为什么数据触发在这里没有捕获或起作用？ （使用静态资源还是使用文字值）？更相关-为什么会出现此错误？ 正在使用（密封） DataTrigger后，无法对其进行修改错误？什么是完成我要在这里完成的正确方法？ （最好还是使用数据触发而不是转换器，因为我确实需要在两个值之间切换）。

So why is the data-trigger not catching or working here? ( Either with the static resource or the literal value )? Even more relevant - why am I getting this error? The "After a 'DataTrigger' is in use (sealed), it cannot be modified" error? And what is the proper method of accomplishing what I am trying to do here? ( Preferably still using a data-trigger and not a converter, since I do need to switch between two values ).