VisualStateManager不会更改UserControl的可见性

Question

请帮助我理解为什么VisualStateManager不会改变 UserControls窗口大小调整时的可见性。 我想在窗口调整大小时用一个用户控件替换另一个用户控件。

这是我的代码：

<Page
x:Class="Diagrams.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Diagrams"
xmlns:uc="using:Diagrams.UserControls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">

<Grid x:Name="RootGrid" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
    <ContentControl>
        <StackPanel>
        <uc:MyUserControl1 x:Name="MyControl1" Visibility="Visible" Height="400" Width="900" />
        <uc:MyUserControl1 x:Name="MyControl2" Visibility="Collapsed" Height="400" Width="900"/>
        </StackPanel>

    </ContentControl>
    <VisualStateManager.VisualStateGroups>
        <VisualStateGroup>
            <VisualState  x:Name="Narrow">
                <VisualState.StateTriggers>
                    <AdaptiveTrigger MinWindowWidth="0" />
                </VisualState.StateTriggers>
                <VisualState.Setters>
                    <Setter Target="RootGrid.Background" Value="White" />
                    <Setter Target="MyControl2.Visibility" Value="Collapsed" />
                    <Setter Target="MyControl1.Visibility" Value="Visible" />
                    <Setter Target="MyControl1.Background" Value="Black" />

                </VisualState.Setters>
            </VisualState>
            <VisualState  x:Name="WideScreen">
                <VisualState.StateTriggers>
                    <AdaptiveTrigger MinWindowWidth="1080" />
                </VisualState.StateTriggers>
                <VisualState.Setters>
                    <Setter Target="RootGrid.Background" Value="Blue" />
                    <Setter Target="MyControl2.Visibility" Value="Visible" />
                    <Setter Target="MyControl1.Visibility" Value="Collapsed" />
                    <Setter Target="MyControl1.Background" Value="Red" />

                </VisualState.Setters>
            </VisualState>
            <VisualState x:Name="Surface">
                <VisualState.StateTriggers>
                    <AdaptiveTrigger MinWindowWidth="1921" />
                </VisualState.StateTriggers>
                <VisualState.Setters>
                    <Setter Target="RootGrid.Background" Value="Black" />
                    <Setter Target="MyControl2.Visibility" Value="Collapsed" />
                    <Setter Target="MyControl1.Visibility" Value="Visible" />
                    <Setter Target="MyControl1.Background" Value="Yellow" />
                </VisualState.Setters>
            </VisualState>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>

</Grid>