在WPF？如何实施ICommandSource给我用命令的XAML自定义控件的能力？ [英] In WPF how do I implement ICommandSource to give my custom control ability to use Command from xaml?

问题描述

请您提供您怎么落实 ICommandSource 界面的样本。正如我希望我的用户控件，它不必在XAML指定命令，有这种能力的能力。并能在用户点击来处理该命令的 CustomControl 。

Could you please provide a sample, of how do you implement the ICommandSource interface. As I want my UserControl, which doesn't have the ability to Specify command in xaml, to have this ability. And to be able to handle the command when user clicks on the CustomControl.

推荐答案

下面是一个例子：

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);
        }
    }

}

请注意， CommandTarget 属性仅用于 RoutedCommands

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