WPF 如何：实现 ICommandSource

本人实在是太懒了，实在是不想引用DLL
所以自定义 MyTextBlock , 使用其MouseLeftClick来触发ICommand

namespace MyControls20210528  {
    class MyTextBlock : TextBlock, ICommandSource
    {
        public static readonly DependencyProperty CommandProperty =
            DependencyProperty.Register("Command", typeof(ICommand), typeof(MyTextBlock),
                new PropertyMetadata((ICommand)null,new PropertyChangedCallback(CommandChanged)));

        public static readonly DependencyProperty CommandParameterProperty = 
            DependencyProperty.Register("CommandParameter", typeof(object), typeof(MyTextBlock));

        public static readonly DependencyProperty CommandTargetProperty = 
            DependencyProperty.Register("CommandTarget", typeof(IInputElement), typeof(MyTextBlock));

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

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

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

        private static void CommandChanged(DependencyObject d,DependencyPropertyChangedEventArgs e)
        {
            MyTextBlock myTxtb = d as MyTextBlock;
            if(myTxtb!=null)
            {
                ICommand oldCommand = e.OldValue as ICommand;
                ICommand newCommand = e.NewValue as ICommand;
                myTxtb.HookUpCommand(oldCommand, newCommand);
            }
        }
        private void HookUpCommand(ICommand oldCommand, ICommand newCommand)
        {
            if (oldCommand != null)
            {
                oldCommand.CanExecuteChanged -= CanExecuteChanged;
            }
            if (newCommand != null)
            {
                newCommand.CanExecuteChanged += CanExecuteChanged;
            }
        }

        private void CanExecuteChanged(object sender, EventArgs e)
        {
            RoutedCommand command = this.Command as RoutedCommand;
            if (command != null)
            {
                this.IsEnabled = command.CanExecute(CommandParameter, CommandTarget);
            }
            else if (this.Command != null)
            {
                this.IsEnabled = this.Command.CanExecute(CommandParameter);
            }
        }

        protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
        {
            base.OnMouseLeftButtonDown(e);
            RoutedCommand command = Command as RoutedCommand;
            if (command != null)
                command.Execute(CommandParameter, CommandTarget);
            else if (Command != null)
                this.Command.Execute(CommandParameter);
        }
    }
}

xaml中如何使用：

xmlns:MyTxtb ="clr-namespace:MyControls20210528  "


  <MyTxtb:MyTextBlock Text="下一个" Command="{Binding CMD_ClickTheLabel}"/>

在Command绑定正确的情况下，鼠标左键能够触发
参考： https://docs.microsoft.com/zh-cn/dotnet/desktop/wpf/advanced/how-to-implement-icommandsource?redirectedfrom=MSDN&view=netframeworkdesktop-4.8