Question

我希望将一个窗口级别的KeyBinding与命令参数作为窗口本身。

e.g。

<KeyBinding Command="{Binding CloseCommand}" CommandParameter="{Binding ElementName=mainWindow}" Key="Esc"/>

绑定有效，但参数为null。有什么工作？

以下是我的命令：`

public class DelegateCommand : ICommand
{
    private readonly Predicate<object> _canExecute;
    private readonly Action<object> _execute;

    public DelegateCommand(Action<object> execute)
        : this(execute, null)
    {
    }

    public DelegateCommand(Action<object> execute,
                   Predicate<object> canExecute)
    {
        if (execute == null)
            throw new ArgumentNullException("Action excute is null");
        _execute = execute;
        _canExecute = canExecute;
    }

    [DebuggerStepThrough]
    public bool CanExecute(object parameter)
    {
        return _canExecute == null ? true : _canExecute(parameter);
    }

    public void Execute(object parameter)
    {
        _execute(parameter);
    }

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

Answer 1

实际上这对我有用 - 但我正在使用[MVVM Light Toolkit 1的RelayCommand<FrameworkElement>。

<Window.InputBindings>
    <KeyBinding Command="{Binding MyCommand, ElementName=MainRoot}" CommandParameter="{Binding ElementName=MainRoot}" Key="Esc"/>
</Window.InputBindings>

就我而言，Command来自DependencyProperty，但这不会产生很大的影响。

public RelayCommand<FrameworkElement> MyCommand
{
    get { return (RelayCommand<FrameworkElement>)GetValue(MyCommandProperty); }
    set { SetValue(MyCommandProperty, value); }
}

// Using a DependencyProperty as the backing store for MyCommand.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty MyCommandProperty =
    DependencyProperty.Register("MyCommand", typeof(RelayCommand<FrameworkElement>), typeof(MainWindow), new PropertyMetadata(null));




public MainWindow()
{
    InitializeComponent();
    MyCommand = new RelayCommand<FrameworkElement>(DoSthYo);
}

public void DoSthYo(FrameworkElement fwE)
{
    var x = fwE; 
}

因为这是有效的 - 我认为你的Command可能不支持CommandParameter。

Answer 2

我的建议是在RelativeSource绑定中使用CommandParameter：

<Window.InputBindings>
    <KeyBinding Command="{x:Static local:CloseWindowCommand.Instance}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}" Key="Esc" />
</Window.InputBindings>

通过这种方式，您的绑定可以与Window的名称无关。然后，您可以创建一个static命令来关闭应用程序的每个窗口：

public class CloseWindowCommand : ICommand
{
    public static readonly ICommand instance = new CloseWindowCommand();
    public event EventHandler CanExecuteChanged;

    private CloseWindowCommand()
    {
    } 

    public bool CanExecute(object parameter)
    {
        return (parameter is Window);
    }

    public void Execute(object parameter)
    {
        Window win;
        if (CanExecute(parameter))
        {
            win = (Window)parameter;
            win.Close();
        }
    }
}

我希望它可以帮到你。

输入绑定CommandParameter绑定到窗口

2 个答案: