如何将keypress与Composite WPF中的DelegateCommand相关联？

Question

我正在使用CAL/Prism构建复合应用程序.主区域是一个选项卡控件,其中包含多种类型的视图.每个视图都有一个可以处理的自定义设置命令,这些命令绑定到窗口顶部的工具栏按钮.我之前在非CAL应用程序中通过简单地在命令上设置InputBinding来完成此操作,但我无法在CAL模块的源代码中找到任何此类机制.

我的问题是,将键击连接到我的视图的最佳方法是什么,这样当用户按下Alt+时T,关联的DelegateCommand对象会处理它？连接快捷方式不是那么困难......

Answer 1

仅供参考,CommandReference类当前未包含在您可以引用的程序集中,但包含在MV-VM项目模板中.因此,如果您不从模板构建应用程序,那么您必须从其他地方获取该类.我选择从示例项目中复制它.我将它包含在下面,以便每个人都能轻松访问这一小块优点,但请确保在未来版本的MV-VM Toolkit中检查模板的更新.

/// <summary>
/// This class facilitates associating a key binding in XAML markup to a command
/// defined in a View Model by exposing a Command dependency property.
/// The class derives from Freezable to work around a limitation in WPF when data-binding from XAML.
/// </summary>
public class CommandReference : Freezable, ICommand
{
    public CommandReference( )
    {
    }
    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register( "Command", typeof( ICommand ), typeof( CommandReference ), new PropertyMetadata( new PropertyChangedCallback( OnCommandChanged ) ) );

    public ICommand Command
    {
        get { return (ICommand)GetValue( CommandProperty ); }
        set { SetValue( CommandProperty, value ); }
    }

    #region ICommand Members

    public bool CanExecute(object parameter)
    {
        if (Command != null)
            return Command.CanExecute( parameter );
        return false;
    }

    public void Execute(object parameter)
    {
        Command.Execute( parameter );
    }

    public event EventHandler CanExecuteChanged;

    private static void OnCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        CommandReference commandReference = d as CommandReference;
        if (commandReference != null)
        {
            ICommand oldCommand = e.OldValue as ICommand;
            if (oldCommand != null)
                oldCommand.CanExecuteChanged -= commandReference.CanExecuteChanged;

            ICommand newCommand = e.NewValue as ICommand;
            if (newCommand != null)
                newCommand.CanExecuteChanged += commandReference.CanExecuteChanged;
        }
    }

    #endregion

    #region Freezable

    protected override Freezable CreateInstanceCore( )
    {
        return new CommandReference();
    }

    #endregion
}

请享用!

Answer 2

该MVVM工具包有一个叫做类CommandReference,让你使用一个参考的命令作为键绑定.

<Window ...
    xmlns:toolkit="clr-namespace:CannotRememberNamspace;assembly=OrTheAssembly"
    >

    <Window.Resources>
        <toolkit:CommandReference 
                 x:Key="ExitCommandReference" 
                 Command="{Binding ExitCommand}" />
    </Window.Resources>

    <Window.InputBindings>
        <KeyBinding Key="X" 
                    Modifiers="Control" 
                    Command="{StaticResource ExitCommandReference}" />
    </Window.InputBindings>
</Window>

这样就行了.

编辑:由于这是编写的,WPF 4.0修复了这个特定问题,您不再需要使用静态资源解决方法.您可以直接从KeyBinding引用viewmodel中的命令.