在WPF中，如何實現ICommandSource以使我的自定義控制能力能夠使用來自xaml的命令？

Question

能否請您提供一個示例，了解如何實現ICommandSource接口。 因為我想要我的UserControl ，它不具備在xaml中指定命令的能力，以具備此功能。 並且能夠在用戶單擊CustomControl時處理該命令。

Answer 1

這是一個例子：

public partial class MyUserControl : UserControl, ICommandSource
{
    public MyUserControl()
    {
        InitializeComponent();
    }



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

    public static readonly DependencyProperty CommandProperty =
        DependencyProperty.Register("Command", typeof(ICommand), typeof(MyUserControl), new UIPropertyMetadata(null));


    public object CommandParameter
    {
        get { return (object)GetValue(CommandParameterProperty); }
        set { SetValue(CommandParameterProperty, value); }
    }

    // Using a DependencyProperty as the backing store for CommandParameter.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty CommandParameterProperty =
        DependencyProperty.Register("CommandParameter", typeof(object), typeof(MyUserControl), new UIPropertyMetadata(null));

    public IInputElement CommandTarget
    {
        get { return (IInputElement)GetValue(CommandTargetProperty); }
        set { SetValue(CommandTargetProperty, value); }
    }

    // Using a DependencyProperty as the backing store for CommandTarget.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty CommandTargetProperty =
        DependencyProperty.Register("CommandTarget", typeof(IInputElement), typeof(MyUserControl), new UIPropertyMetadata(null));


    protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
    {
        base.OnMouseLeftButtonUp(e);

        var command = Command;
        var parameter = CommandParameter;
        var target = CommandTarget;

        var routedCmd = command as RoutedCommand;
        if (routedCmd != null && routedCmd.CanExecute(parameter, target))
        {
            routedCmd.Execute(parameter, target);
        }
        else if (command != null && command.CanExecute(parameter))
        {
            command.Execute(parameter);
        }
    }

}

請注意， CommandTarget屬性僅用於RoutedCommands

Answer 2

您的UserControl將在文件cs或vb后面有一個代碼，您必須實現接口ICommandSource，一旦實現它，在某些情況下您將必須實際調用該命令並檢查CanExecute。