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在绑定数据变化时手动触发UI状态检查

<Window x:Class="WpfApp5.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:WpfApp5"mc:Ignorable="d"Title="MainWindow" Height="450" Width="800"><Window.DataContext><local:MainViewModel /></Window.DataContext><StackPanel HorizontalAlignment="Center" VerticalAlignment="Center"><Button Content="点击"  Command="{Binding ClickCommand}"  Margin="10" Padding="15" /><Button Content="Sub"  Command="{Binding ClickCommandSub}"  Margin="10" Padding="15" /><TextBlock Text="{Binding Count, StringFormat='已点击次数: {0}'}"  HorizontalAlignment="Center" Width="80" Margin="10"/></StackPanel>
</Window>

public partial class MainWindow : Window
{public MainWindow(){InitializeComponent();DataContext = new MainViewModel();}
}public class ManualRelayCommand : ICommand
{private readonly Action<object> _execute;private readonly Func<object, bool> _canExecute;public ManualRelayCommand(Action<object> execute, Func<object, bool> canExecute = null){_execute = execute;_canExecute = canExecute;}public bool CanExecute(object parameter) => _canExecute?.Invoke(parameter) ?? true;public void Execute(object parameter) => _execute(parameter);// 手动触发事件  public event EventHandler CanExecuteChanged;public void RaiseCanExecuteChanged() => CanExecuteChanged?.Invoke(this, EventArgs.Empty);//public event EventHandler CanExecuteChanged//{//    add => CommandManager.RequerySuggested += value;//    remove => CommandManager.RequerySuggested -= value;//} 同时保留手动触发方法  //public void ForceRaiseCanExecuteChanged() => CommandManager.InvalidateRequerySuggested();
}public class MainViewModel : INotifyPropertyChanged
{public event PropertyChangedEventHandler PropertyChanged;protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)=> PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));private int _count;public int Count{get => _count;set{if (_count == value) return;_count = value;OnPropertyChanged();// 手动触发命令状态更新  ClickCommand.RaiseCanExecuteChanged();}}public ManualRelayCommand ClickCommand { get; }public ICommand ClickCommandSub{get { return new ManualRelayCommand(_ => Count--, _ => true); }set { }}public MainViewModel(){ClickCommand = new ManualRelayCommand(ClickEvent,_CanExecute );}private void ClickEvent(object obj){Count++;}private bool _CanExecute(object arg){return Count < 3;}
}