WPF DataBinding未更新属性

Question

我有一个WPF项目，我正在使用自定义标题栏。在制作最小化/最大化按钮时，我发现了一些对我来说没有多大意义的东西。当我在控件上显式设置Visibility属性时，触发器不再能够更新该属性。我已经验证了使用WPF Inspector正确触发了触发器，当我没有明确设置Visibility属性而是让它从触发器中获取值时，它可以正常工作。 / p>

我知道我不能明确地设置属性并且有一个可行的解决方案;然而，这似乎违背了我对触发器应该如何运作的了解。实际上，我正在寻找一个解释，说明它为什么不起作用，如果可能的话，在明确设置属性时如何使其工作。

这是我完整的WPF示例应用程序，它非常模仿我尝试做的事情。当Collapsed从Visible转到WindowState时，Maximized按钮应取代Normal按钮，反之亦然。最后一列上的按钮是在未明确设置属性的情况下工作的按钮。

<Window x:Class="ButtonVisibilityTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ButtonVisibilityTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <Style x:Key="btn" TargetType="{x:Type Button}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Border Background="Transparent">
                            <ContentPresenter />
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>

            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="{x:Type Button}">
                                <Border Background="#E6E6E6">
                                    <ContentPresenter />
                                </Border>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
                <Trigger Property="IsPressed" Value="True">
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="{x:Type Button}">
                                <Border Background="#C6C6C6">
                                    <ContentPresenter />
                                </Border>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition Width="48" />
            <ColumnDefinition Width="48" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="32"/>
            <RowDefinition/>
        </Grid.RowDefinitions>

        <Button Grid.Column="1" Foreground="#000000">
            <Grid Width="8" Height="8">
                <Rectangle Stroke="{Binding Foreground, RelativeSource={RelativeSource AncestorType={x:Type Button}}}" StrokeThickness="1" Width="9" Height="9"/>
            </Grid>

            <Button.Style>
                <Style TargetType="{x:Type Button}" BasedOn="{StaticResource btn}">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Normal">
                            <Setter Property="Visibility" Value="Visible"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Maximized">
                            <Setter Property="Visibility" Value="Collapsed"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Button.Style>
        </Button>

        <!-- Doesn't Work -->
        <Button Grid.Column="1" Foreground="#000000" Visibility="Collapsed">
            <Grid Width="8" Height="8">
                <Rectangle Stroke="{Binding Foreground, RelativeSource={RelativeSource AncestorType={x:Type Button}}}" StrokeThickness="1" Width="9" Height="1"/>
            </Grid>

            <Button.Style>
                <Style TargetType="{x:Type Button}" BasedOn="{StaticResource btn}">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Normal">
                            <Setter Property="Visibility" Value="Collapsed"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Maximized">
                            <Setter Property="Visibility" Value="Visible"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Button.Style>
        </Button>

        <!-- Works -->
        <Button Grid.Column="2" Foreground="#000000">
            <Grid Width="8" Height="8">
                <Rectangle Stroke="{Binding Foreground, RelativeSource={RelativeSource AncestorType={x:Type Button}}}" StrokeThickness="1" Width="9" Height="1"/>
            </Grid>

            <Button.Style>
                <Style TargetType="{x:Type Button}" BasedOn="{StaticResource btn}">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Normal">
                            <Setter Property="Visibility" Value="Collapsed"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=WindowState}" Value="Maximized">
                            <Setter Property="Visibility" Value="Visible"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Button.Style>
        </Button>
    </Grid>
</Window>