MVVM 中 ViewModelBase和 CommandBase

 public class ViewModelBase : INotifyPropertyChanged , IDisposable
     {
         public virtual string DisplayName { get; protected set; }  

         public event PropertyChangedEventHandler PropertyChanged;

         protected void OnPropertyChanged([CallerMemberName]string propertyName = null)
         {
             if (PropertyChanged != null)
             {
                 PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
             }
         }

         public void Dispose()
         {
             this.OnDispose();
         }

         /// <summary>
         /// 若支持IDisposable，请重写此方法，当被调用Dispose时会执行此方法。
         /// </summary>
         protected virtual void OnDispose()
         {

         }
     }

 public class CommandBase : ICommand
    {
        private readonly Action<object> _command;
        private readonly Func<object, bool> _canExecute;

        public CommandBase(Action<object> command, Func<object, bool> canExecute)
        {
            if (command == null)
                throw new ArgumentNullException("command");
            _canExecute = canExecute;
            _command = command;
        }

        public bool CanExecute(object parameter)
        {
            if (_canExecute == null)
                return true;
            return _canExecute(parameter);
        }

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }  

        public void Execute(object parameter)
        {
            _command(parameter);
        }
    }