WinUI3窗口最大化后拖拽区域异常问题及延迟修复方案

问题现象 #

• 调试阶段，captionsregion和TabViewItem均不可拖拽，功能正常
• 窗口最大化后，TabViewItem变为可拖拽移动，且失去拖出窗口的功能
• 新增标签后拖拽区域恢复正常，但这不是理想解决方案

相关代码 #

TabViewControl可视化树 #

<Grid>
    <TabView x:Name="MyTabView" Background="Transparent" AddTabButtonClick="MyTabView_AddTabButtonClick" TabCloseRequested="MyTabView_TabCloseRequested">

        <!--自定义左侧区域-->
        <TabView.TabStripHeader>
            <Border x:Name="MyCustomMenuRegion" MinWidth="0" Background="Transparent" IsHitTestVisible="False"/>
        </TabView.TabStripHeader>

        <!--默认首页标签-->
        <TabViewItem Header="Home" Background="Transparent" IsClosable="False" MaxHeight="40" MaxWidth="50">
        </TabViewItem>

        <!--自定义右侧拖拽区域-->
        <TabView.TabStripFooter>
            <Border x:Name="CustomDragRegion" MinWidth="0" Background="Transparent" IsHitTestVisible="False" SizeChanged="CustomDragRegion_SizeChanged"/>
        </TabView.TabStripFooter>
    </TabView>
</Grid>

UserWindow(MainWindow)可视化树 #

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="40" x:Name="TitleBarRegion"/>
        <RowDefinition Height="*" x:Name="ContentRegion"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*" x:Name="ControlRegion"/>
    </Grid.ColumnDefinitions>

    <myUICrl:MyTitleRegionControl x:Name="MyTitleRegion" Grid.Row="0" Grid.Column="0" Canvas.ZIndex="0"/>

    <myUICrl:MyCaptionsRegionControl x:Name="MyCaptionsRegion" Grid.Row="0" Grid.Column="1" Canvas.ZIndex="2" HorizontalAlignment="Right"/>

    <myUICrl:MyTabViewControl x:Name="MyTabView" Grid.Row="0" Grid.Column="0" Canvas.ZIndex="1"/>
</Grid>

后台SetDragRegion相关代码 #

private void MyUserWindow_SizeChanged(object sender, WindowSizeChangedEventArgs args)
{
    this.MyCaptionsRegion.OnWindowStateChanged();

    if (this.MyTitleRegion.XamlRoot != null)
    { SetRegionsForCustomTitleBar(); }
}

internal void SetRegionsForCustomTitleBar()
{
    double scale = this.MyTitleRegion.XamlRoot.RasterizationScale;

    // 设置标题栏宽度
    SetTitleBarWidth(this.AppWindow, this.MyTitleRegion, scale);

    // 设置标题栏可拖拽区域
    SetDraggableArea(this.AppWindow, this.MyTabView, scale);

    // 设置标题栏按钮不可拖拽区域
    SetNonDraggableRegion(this.AppWindow, this.MyCaptionsRegion, scale);
}

private void SetTitleBarWidth(AppWindow myAppWindow, MyTitleRegionControl myTitleRegion, double scale)
{
    myTitleRegion.GetHeaderDefinition().Width = new GridLength(myAppWindow.TitleBar.LeftInset / scale);
    myTitleRegion.GetFooterDefinition().Width = new GridLength(myAppWindow.TitleBar.RightInset / scale);
}

private void SetDraggableArea(AppWindow myAppWindow, MyTabViewControl myTabView, double scale)
{
    Border myCustomDragRegion = myTabView.GetCustomDragRegion();
    GeneralTransform customDragRegionTransform = myCustomDragRegion.TransformToVisual(null);
    Rect customDragRegionBounds = customDragRegionTransform.TransformBounds(new Rect(0, 0, myCustomDragRegion.ActualWidth, myCustomDragRegion.ActualHeight));
    RectInt32 customDragRegionRect = GetRect(customDragRegionBounds, scale);

    Trace.WriteLine($"[SetDraggableArea] Bounds: X={customDragRegionBounds.X}, Y={customDragRegionBounds.Y}, W={customDragRegionBounds.Width}, H={customDragRegionBounds.Height}");
    Trace.WriteLine($"[SetDraggableArea] Scaled Rect: X={customDragRegionRect.X}, Y={customDragRegionRect.Y}, W={customDragRegionRect.Width}, H={customDragRegionRect.Height}");

    myAppWindow.TitleBar.SetDragRectangles(GetRectArray(customDragRegionRect));
}

private void SetNonDraggableRegion(AppWindow myAppWindow, MyCaptionsRegionControl myCaptionsRegion, double scale)
{
    GeneralTransform captionsRegionTransform = myCaptionsRegion.TransformToVisual(null);
    Rect captionsRegionBounds = captionsRegionTransform.TransformBounds(new Rect(0, 0, myCaptionsRegion.ActualWidth, myCaptionsRegion.ActualHeight));
    RectInt32 captionsRegionRect = GetRect(captionsRegionBounds, scale);

    InputNonClientPointerSource nonClientInputSrc = InputNonClientPointerSource.GetForWindowId(myAppWindow.Id);
    nonClientInputSrc.SetRegionRects(NonClientRegionKind.Passthrough, GetRectArray(captionsRegionRect));
}

private RectInt32 GetRect(Rect bounds, double scale)
{
    return new RectInt32
    (
        _X: (int)Math.Round(bounds.X * scale),
        _Y: (int)Math.Round(bounds.Y * scale),
        _Width: (int)Math.Round(bounds.Width * scale),
        _Height: (int)Math.Round(bounds.Height * scale)
    );
}

private RectInt32[] GetRectArray(RectInt32 rect)
{
    return new RectInt32[] { rect };
}

测试数据 #

• 启动时：

  [SetDraggableArea] Bounds: X=97, Y=0, W=1327, H=40
  [SetDraggableArea] Scaled Rect: X=97, Y=0, W=1327, H=40
  

• 最大化后：

  [SetDraggableArea] Bounds: X=97, Y=0, W=1823, H=40
  [SetDraggableArea] Scaled Rect: X=97, Y=0, W=1823, H=40
  

• 恢复后：

  [SetDraggableArea] Bounds: X=97, Y=0, W=1327, H=40
  [SetDraggableArea] Scaled Rect: X=97, Y=0, W=1327, H=40
  

修复方案 #

1. 移除MyUserWindow_SizeChanged事件中的SetRegionsForCustomTitleBar调用：

private void MyUserWindow_SizeChanged(object sender, WindowSizeChangedEventArgs args)
{
    this.MyCaptionsRegion.OnWindowStateChanged();
}

2. 给TabStripFooter的CustomDragRegion添加SizeChanged事件，需加入50ms延迟否则问题仍存在：

private async void CustomDragRegion_SizeChanged(object sender, SizeChangedEventArgs args)
{
    await Task.Delay(50);
    ManageWindows.GetUserWindow().SetRegionsForCustomTitleBar();
}

内容的提问来源于stack exchange，提问作者Pain Nncera