概述：我有两个属性：

1. IsPast
2. IsCurrentMonth
   如果是过去的月份或不是当前月份，我希望以红色显示标签。
   下面的代码是默认Maui应用程序的收缩版本。如果你运行它，你会得到红色标签（预期的）。在一次点击后，它保持红色（预期的），但随后的点击会切换红色的开关。这是一个bug还是我不明白DataTrigger/Style/whatever的工作方式：
   查看型号：

public class ViewModel : INotifyPropertyChanged
    {
        private bool _isPast;
        public bool IsPast
        {
            get => _isPast;
            set
            {
                _isPast = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsPast)));
            }
        }

        private bool _isCurrentMonth;
        public bool IsCurrentMonth
        {
            get => _isCurrentMonth;
            set
            {
                _isCurrentMonth = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsCurrentMonth)));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }

然后XAML：

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:BugMaui"
             x:Class="BugMaui.MainPage"
             x:DataType="local:ViewModel">

    <VerticalStackLayout>

        <HorizontalStackLayout>
            <Label Text="IsPast: " />
            <Label Text="{Binding IsPast}" />
        </HorizontalStackLayout>

        <HorizontalStackLayout>
            <Label Text="IsCurrentMonth: " />
            <Label Text="{Binding IsCurrentMonth}" />
        </HorizontalStackLayout>

        <Label
            Text="Hello, World!"
            FontSize="32"
            HorizontalOptions="Center">
            <Label.Style>
                <Style TargetType="Label">
                    <Style.Triggers>
                        <DataTrigger TargetType="Label" Binding="{Binding IsPast}" Value="True">
                            <Setter Property="Background" Value="Red" />
                        </DataTrigger>
                        <DataTrigger TargetType="Label" Binding="{Binding IsCurrentMonth}" Value="False">
                            <Setter Property="Background" Value="Red" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Label.Style>
        </Label>

        <Button
            Text="Click me"
            Clicked="OnCounterClicked"/>

    </VerticalStackLayout>

</ContentPage>

而背后的代码：

public partial class MainPage : ContentPage
{
    ViewModel viewModel;

    public MainPage()
    {
        InitializeComponent();
        viewModel = new ViewModel { IsCurrentMonth = true, IsPast = true };
        BindingContext = viewModel;
    }

    private void OnCounterClicked(object sender, EventArgs e)
    {
        viewModel.IsPast = !viewModel.IsPast;
        viewModel.IsCurrentMonth = !viewModel.IsCurrentMonth;
    }
}