如何在 WPF 中捕获按键？答案

【问题标题】：How do I capture key down in WPF?如何在 WPF 中捕获按键？
【发布时间】：2010-11-24 11:47:31
【问题描述】：

即使我的应用程序没有获得焦点，如何在 WPF 中捕获按键事件？

【问题讨论】：

【解决方案1】：

对我来说，最好的方法是：

public MainWindow()
{
    InitializeComponent();

    CompositionTarget.Rendering += new EventHandler(CompositionTarget_Rendering);
}

void CompositionTarget_Rendering(object sender, EventArgs e)
{
    if ((Keyboard.GetKeyStates(Key.W) & KeyStates.Down) > 0)
    {
        player1.walk();
    }
}

渲染事件每次都会运行。

【讨论】：

【解决方案2】：

全局键盘挂钩会减慢您的调试速度。

我更喜欢使用这种方法：

创建键盘监听类

public class KeyboardListener : IDisposable
{
    private readonly Thread keyboardThread;

    //Here you can put those keys that you want to capture
    private readonly List<KeyState> numericKeys = new List<KeyState>
    {
        new KeyState(Key.D0),
        new KeyState(Key.D1),
        new KeyState(Key.D2),
        new KeyState(Key.D3),
        new KeyState(Key.D4),
        new KeyState(Key.D5),
        new KeyState(Key.D6),
        new KeyState(Key.D7),
        new KeyState(Key.D8),
        new KeyState(Key.D9),
        new KeyState(Key.NumPad0),
        new KeyState(Key.NumPad1),
        new KeyState(Key.NumPad2),
        new KeyState(Key.NumPad3),
        new KeyState(Key.NumPad4),
        new KeyState(Key.NumPad5),
        new KeyState(Key.NumPad6),
        new KeyState(Key.NumPad7),
        new KeyState(Key.NumPad8),
        new KeyState(Key.NumPad9),
        new KeyState(Key.Enter)
    };

    private bool isRunning = true;

    public KeyboardListener()
    {
        keyboardThread = new Thread(StartKeyboardListener) { IsBackground = true };
        keyboardThread.Start();
    }

    private void StartKeyboardListener()
    {
        while (isRunning)
        {
            Thread.Sleep(15);
            if (Application.Current != null)
            {
                Application.Current.Dispatcher.Invoke(() =>
                {
                    if (Application.Current.Windows.Count > 0)
                    {
                        foreach (var keyState in numericKeys)
                        {
                            if (Keyboard.IsKeyDown(keyState.Key) && !keyState.IsPressed) //
                            {
                                keyState.IsPressed = true;
                                KeyboardDownEvent?.Invoke(null, new KeyEventArgs(Keyboard.PrimaryDevice, PresentationSource.FromDependencyObject(Application.Current.Windows[0]), 0, keyState.Key));
                            }

                            if (Keyboard.IsKeyUp(keyState.Key))
                            {
                                keyState.IsPressed = false;
                            }
                        }
                    }
                });
            }
        }
    }

    public event KeyEventHandler KeyboardDownEvent;

    /// <summary>
    /// Состояние клавиши
    /// </summary>
    private class KeyState
    {
        public KeyState(Key key)
        {
            this.Key = key;
        }

        public Key Key { get; }
        public bool IsPressed { get; set; }
    }

    public void Dispose()
    {
        isRunning = false;
        Task.Run(() =>
        {
            if (keyboardThread != null && !keyboardThread.Join(1000))
            {
                keyboardThread.Abort();
            }
        });
    }
}

在代码隐藏（或您需要的地方）订阅 KeyboardDownEvent。

public partial class MainWindow : Window
{
    private KeyboardListener listener;

    public MainWindow()
    {
        InitializeComponent();
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        listener = new KeyboardListener();
        listener.KeyboardDownEvent += ListenerOnKeyPressed;
    }

    private void ListenerOnKeyPressed(object sender, KeyEventArgs e)
    {
        // TYPE YOUR CODE HERE
    }

    private void Window_OnUnloaded(object sender, RoutedEventArgs e)
    {
        listener.KeyboardDownEvent -= ListenerOnKeyPressed;
    }
}

完成

【讨论】：

【解决方案3】：

请参阅此问题以了解键盘Using global keyboard hook (WH_KEYBOARD_LL) in WPF / C#

【讨论】：