实现键盘快捷键

Question

我目前使用onKeyDown事件和if/else语句来创建键盘快捷键：

if ((Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift && e.Key == Key.Tab) {

} else if (e.Key == Key.Tab) {

} ...

然而，如果我有相当多的键盘快捷键，这就会变得混乱。

有没有更好的实现？

Answer 1

您应该考虑实现和

<Window.CommandBindings>
    <CommandBinding Command="Settings" CanExecute="SettingsCanExecute" Executed="SettingsExecuted" />
</Window.CommandBindings>

<Window.InputBindings>
    <KeyBinding Command="Settings" Key="S" Modifiers="Alt" />
</Window.InputBindings>

然后，您的<Button>将变为：

<Button Height="50" Width="50" Margin="50,5,0,0" Command="Settings" />

SettingsCanExecute方法确定何时启用按钮，并在按下按钮或按下组合键时调用SettingsExecuted方法。

这样就不需要KeyDown处理程序了。

代码上有一个full tutorial on开关。

关于CommandBindings和InputBindings的更多信息可以在MSDN上找到。

Answer 2

为其他人记录这个答案，因为有一种很少被引用的更简单的方法，而且根本不需要接触XAML。

要链接键盘快捷键，只需在窗口构造函数中向InputBindings集合添加一个新的KeyBinding即可。作为命令，传入实现ICommand的任意命令类。对于execute方法，只需实现所需的任何逻辑。在下面的示例中，我的WindowCommand类接受一个委托，它将在每次调用时执行该委托。当我构造新的WindowCommand来传入我的绑定时，我只是在我的初始化器中指示我想要WindowCommand执行的方法。

您可以使用此模式提供您自己的快速键盘快捷键。

public YourWindow() //inside any WPF Window constructor
{
   ...
   //add this one statement to bind a new keyboard command shortcut
   InputBindings.Add(new KeyBinding( //add a new key-binding, and pass in your command object instance which contains the Execute method which WPF will execute
      new WindowCommand(this)
      {
         ExecuteDelegate = TogglePause //REPLACE TogglePause with your method delegate
      }, new KeyGesture(Key.P, ModifierKeys.Control)));
   ...
}

创建一个简单的WindowCommand类，它接受一个执行委托来触发在它上面设置的任何方法。

public class WindowCommand : ICommand
{
    private MainWindow _window;

    //Set this delegate when you initialize a new object. This is the method the command will execute. You can also change this delegate type if you need to.
    public Action ExecuteDelegate { get; set; }

    //You don't have to add a parameter that takes a constructor. I've just added one in case I need access to the window directly.
    public WindowCommand(MainWindow window)
    {
        _window = window;
    }

    //always called before executing the command, mine just always returns true
    public bool CanExecute(object parameter)
    {
        return true; //mine always returns true, yours can use a new CanExecute delegate, or add custom logic to this method instead.
    }

    public event EventHandler CanExecuteChanged; //i'm not using this, but it's required by the interface

    //the important method that executes the actual command logic
    public void Execute(object parameter)
    {
        if (ExecuteDelegate != null) //let's make sure the delegate was set
        {
            ExecuteDelegate();
        }
        else
        {
            throw new InvalidOperationException("ExecuteDelegate has not been set. There is no method to execute for this command.");
        }
    }
}