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我有一个带有这个网格的控件：

<Grid SizeChanged="Grid_SizeChanged" MaxWidth="{x:Static local:PaneCtrl.MAX_NO_SCALE_WIDTH}">
    <Viewbox MaxHeight="32" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="0,0,0,5">
        <DockPanel Width="{x:Static local:PaneCtrl.MAX_NO_SCALE_WIDTH}">
            <StackPanel x:Name="PlaybackButtons" Orientation="Horizontal" Height="32" HorizontalAlignment="Center" >
                <StackPanel.Effect>
                    <DropShadowEffect ShadowDepth="1" />
                </StackPanel.Effect>
                <Button x:Name="CornerRewind" Style="{StaticResource ImageButtonStyle}"  PreviewMouseLeftButtonDown="CornerPlayerControlFastBackward" >
                    <Image Source="/Pics/FastBackBtn.png" />
                </Button>
                <Button x:Name="CornerStop" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlStop" >
                    <Image Source="/Pics/StopBtn.png" />
                </Button>
                <Button x:Name="CornerPlay" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlPlay" >
                    <Image Source="/Pics/PlayBtn.png"/>
                </Button>
                <Button x:Name="CornerPause" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlPause" >
                    <Image Source="/Pics/PauseBtn.png"/>
                </Button>
                <Button x:Name="CornerFastForward" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlFastForward" >
                    <Image Source="/Pics/FastFwdBtn.png"/>
                </Button>
                <Button x:Name="CornerStepBack" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlBackAfewSec" >
                    <Image Source="/Pics/BackAfewSecBtn.png"/>
                </Button>
                <Button x:Name="CornerGoToLive" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlLive" >
                    <Image Source="/Pics/LiveBtn.png"/>
                </Button>
            </StackPanel>
        </DockPanel>
    </Viewbox>
</Grid>

此 XAML 所做的是，当它被放置在 Width >= PaneCtrl.MAX_NO_SCALE_WIDTH 的容器中时，它会以原始大小显示按钮，但是当它被放置在宽度 < PaneCtrl.MAX_NO_SCALE_WIDTH 的容器中时，它会缩小按钮。

我想在代码中达到相同的效果。不要问我为什么——解释起来需要很长时间。

所以我删除了 ViewBox 和其他使它发生的元素，留下了这个 XAML：

<Grid SizeChanged="Grid_SizeChanged" >
    <StackPanel x:Name="PlaybackButtons" Orientation="Horizontal" Height="32"  HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="0,0,0,5">
        <StackPanel.Effect>
            <DropShadowEffect ShadowDepth="1" />
        </StackPanel.Effect>
        <Button x:Name="CornerRewind" Style="{StaticResource ImageButtonStyle}"  PreviewMouseLeftButtonDown="CornerPlayerControlFastBackward" >
            <Image Source="/Pics/FastBackBtn.png" />
        </Button>
        <Button x:Name="CornerStop" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlStop" >
            <Image Source="/Pics/StopBtn.png" />
        </Button>
        <Button x:Name="CornerPlay" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlPlay" >
            <Image Source="/Pics/PlayBtn.png"/>
        </Button>
        <Button x:Name="CornerPause" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlPause" >
            <Image Source="/Pics/PauseBtn.png"/>
        </Button>
        <Button x:Name="CornerFastForward" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlFastForward" >
            <Image Source="/Pics/FastFwdBtn.png"/>
        </Button>
        <Button x:Name="CornerStepBack" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlBackAfewSec" >
            <Image Source="/Pics/BackAfewSecBtn.png"/>
        </Button>
        <Button x:Name="CornerGoToLive" Style="{StaticResource ImageButtonStyle}" PreviewMouseLeftButtonDown="CornerPlayerControlLive" >
            <Image Source="/Pics/LiveBtn.png"/>
        </Button>
    </StackPanel>
</Grid>

然后我添加了调整大小事件处理程序：

    private void Grid_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        if (e.NewSize.Width < PaneCtrl.MAX_NO_SCALE_WIDTH)
        {
            double scale = e.NewSize.Width / PaneCtrl.MAX_NO_SCALE_WIDTH;
            PlaybackButtons.RenderTransform = new ScaleTransform(scale, scale, PlaybackButtons.ActualWidth / 2, PlaybackButtons.ActualHeight);
        }
        else
        {
            PlaybackButtons.RenderTransform = null;
        }
    }

我看到的是它的行为方式类似，但是当容器宽度太小以至于原始大小的一些按钮会被切掉（未显示）时，它们在我缩放 StackPanel 后也不会显示，即使应该现在有足够的空间来展示它们。

所以很自然我的问题是为什么？

可能是因为 WPF 首先确定它们需要隐藏，然后引发 SizeChanged 事件，允许我缩放它们，之后不会“重新排列”它们。

我应该挂钩一个不同的事件还是应该调用一些东西来强制 WPF“重新安排”或什么？

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