.NET MAUI标题栏颜色异常Bug是否存在可行解决方案？

问题现象 #

搭建极简.NET MAUI项目，包含3个页面，通过Shell导航实现两种跳转路径：

• 页面A通过绝对路径//SecondPage/ModalPage导航至页面C
• 页面B通过相对路径ModalPage将页面C推入导航栈

两种路径从C返回后均回到页面B，但出现不一致现象：

• B→C→返回B：页面B的标题栏颜色保持正常
• A→B/C→返回B：页面B的标题栏意外变为深灰色，离开B页面再返回后颜色恢复正常

测试环境 #

Pixel 5 Android 13 API 33模拟器，使用设备物理返回键或页面内返回按钮触发问题，现象一致。

更新说明 #

该疑似Bug已提交至.NET MAUI官方GitHub问题专区。

问题演示 #

完整项目代码 #

AppShell代码 #

<Shell
    x:Class="TitleBarTest.AppShell"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:TitleBarTest"
    Shell.FlyoutBehavior="Flyout">
    <FlyoutItem Title="Title Bar Test">
        <ShellContent ContentTemplate="{DataTemplate local:MainPage}"
                      Shell.FlyoutItemIsVisible="True"
                      Shell.TabBarIsVisible="True"
                      Title="Page A" 
                      Route="MainPage"/>
        <ShellContent ContentTemplate="{DataTemplate local:SecondPage}"
                      Shell.FlyoutItemIsVisible="True"
                      Shell.TabBarIsVisible="True"
                      Title="Page B"
                      Route="SecondPage"/>
    </FlyoutItem>
    <ShellContent ContentTemplate="{DataTemplate local:ModalPage}"
                  Shell.FlyoutItemIsVisible="False"
                  Shell.TabBarIsVisible="False"
                  Title="Page C" 
                  Route="ModalPage"/>
</Shell>

Page A（MainPage） #

XAML布局

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:TitleBarTest"
             x:DataType="local:MainPageViewModel"
             x:Class="TitleBarTest.MainPage"
             Title="Page A">
    <VerticalStackLayout>
        <Label 
            Text="List of A-items"
            VerticalOptions="Center" 
            HorizontalOptions="Center" />
        <Button
                Command="{Binding GoToModalViaSecondPageCommand}"
                x:Name="CounterBtn"
                Text="Go to C via B"
                HorizontalOptions="Center" />
    </VerticalStackLayout>
</ContentPage>

ViewModel逻辑

public class MainPageViewModel : BaseViewModel
{
    public Command GoToModalViaSecondPageCommand { get; private set; }

    public MainPageViewModel()
    {
        GoToModalViaSecondPageCommand = new Command(GoToModalViaSecondPage);
    }

    public async void GoToModalViaSecondPage()
    {
        await Shell.Current.GoToAsync($"//{nameof(SecondPage)}/{nameof(ModalPage)}");
    }
}

Page B（SecondPage） #

XAML布局

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:TitleBarTest"
             x:DataType="local:SecondPageViewModel"
             x:Class="TitleBarTest.SecondPage"
             Title="Page B">
    <VerticalStackLayout>
        <Label 
            Text="List of B-items"
            VerticalOptions="Center" 
            HorizontalOptions="Center" />
        <Button
                Command="{Binding GoToModalDirectlyCommand}"
                x:Name="CounterBtn"
                Text="Click me"
                SemanticProperties.Hint="Counts the number of times you click"
                HorizontalOptions="Center" />
    </VerticalStackLayout>
</ContentPage>

ViewModel逻辑

public class SecondPageViewModel : BaseViewModel
{
    public Command GoToModalDirectlyCommand { get; private set; }

    public SecondPageViewModel()
    {
        GoToModalDirectlyCommand = new Command(GoToModalDirectly);
    }

    public async void GoToModalDirectly()
    {
        await Shell.Current.GoToAsync($"{nameof(ModalPage)}");
    }
}

Page C（ModalPage） #

XAML布局

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:TitleBarTest"
             x:DataType="local:ModalPageViewModel"
             x:Class="TitleBarTest.ModalPage"
             Shell.PresentationMode="ModalAnimated"
             BackgroundColor="#AA000000"
             Title="Page C">
    <StackLayout VerticalOptions="End">
        <Frame BackgroundColor="White"
               CornerRadius="24"
               HeightRequest="256"
               Margin="0,0,0,-24">
            <VerticalStackLayout>
                <Label 
                    Text="Create new B-item"
                    VerticalOptions="Center" 
                    HorizontalOptions="Center" />
            </VerticalStackLayout>
        </Frame>
    </StackLayout>
</ContentPage>

ViewModel逻辑

public class ModalPageViewModel : BaseViewModel
{
    public Command BackToPageBCommand { get; private set; }

    public ModalPageViewModel()
    {
        BackToPageBCommand = new Command(BackToPageB);
    }

    public async void BackToPageB()
    {
        await Shell.Current.GoToAsync($"//{nameof(SecondPage)}");
    }
}

Styles.xaml默认配置补充 #

针对评论反馈：Shell.BackgroundColor默认在Styles.xaml中定义，移除该设置后所有标题栏会变为灰色，存在默认回退颜色，默认代码如下：

<Style TargetType="Shell" ApplyToDerivedTypes="True">
    <Setter Property="Shell.BackgroundColor" Value="{AppThemeBinding Light={StaticResource Primary}, Dark={StaticResource Gray950}}" />
    ...
    ...
    ...
</Style>

内容的提问来源于stack exchange，提问作者user7862339