一、Command类的创建 >> 构造函数方法中传入了一个委托
public class MyCommand : ICommand
 {
     public readonly Action _action;
     public MyCommand(Action action) { 
         this._action = action;
     }
     public event EventHandler CanExecuteChanged;
    public bool CanExecute(object parameter)
     {
         return true;
     }
    public void Execute(object parameter)
     {
         _action();
     }
 }
二、command在viewmodel中的使用
public class MainViewModel
 {
     public MyCommand myCommand { get; set; }
     public MainViewModel() {
         myCommand = new MyCommand(Show);
     }
     public void Show()
     {
         MessageBox.Show("你点击了我!");
     }
}
三、在页面控件button 中调用
<Button Command="{Binding myCommand}">点击</Button>