向TabView添加标签时自定义标题栏拖拽区域状态异常问题

算力阿峰

2026-6-14

问题：TabView添加标签页时标题栏拖拽区域状态反复切换且XAML调试工具栏跳动

当向TabView中添加新标签页时，标题栏拖拽区域（titlebar drag region）会在启用与禁用状态间反复切换，视觉上无明显变化，但每次添加标签都会触发该状态变更，同时XAML Debug toolbar会出现上下跳动的现象。

最小复现示例

XAML代码

<Window
    x:Class="TitleBar_Bug_Test.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:TitleBar_Bug_Test"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Title="TitleBar Bug Test">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="48"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <TabView Grid.Row="1" AddTabButtonClick="TabView_AddTabButtonClick"/>
    </Grid>
    
</Window>

C#代码

public sealed partial class MainWindow : Window
{
    public MainWindow()
    {
        this.InitializeComponent();

        Microsoft.UI.Windowing.AppWindow appWindow = this.AppWindow;
        var titleBar = appWindow.TitleBar;
        titleBar.ExtendsContentIntoTitleBar = true;
        titleBar.PreferredHeightOption = TitleBarHeightOption.Tall;
    }

    private void TabView_AddTabButtonClick(TabView sender, object args)
    {
        var newTab = new TabViewItem();
        newTab.IconSource = new SymbolIconSource() { Symbol = Symbol.Document };
        newTab.Header = "New Page";

        // The Content of a TabViewItem is often a frame which hosts a page.
        Frame frame = new Frame();
        newTab.Content = frame;
        frame.Navigate(typeof(TestPage));

        sender.TabItems.Add(newTab);
    }
}