WPF自定义控件，聚合器模式传递消息

背景：自定义控件的消息传递和方法的调用可以使用聚合器来进行

定义聚合器：

public class EventAggregator
{
    public static ConcurrentDictionary> _handles = new ConcurrentDictionary>();

    // 订阅方法
    public void Register (Action action)
    {
        if (!_handles.ContainsKey(typeof (T)))
        {
            _handles[typeof (T)] = new List> ();
        }
        
        _handles[typeof(T)].Add(action);

        Debug.WriteLine(_handles[typeof(T)].Count);
    }

    // 给数据给调用的方法
    public void Send (object obj)
    {
        if (_handles.ContainsKey(typeof(T)))
        {
            foreach (var actionin in _handles[typeof(T)])
            {
                actionin?.Invoke(obj);
            }
        }
    }

}

使用单例模式访问聚合器：

public class EventAggregatorRepository
{
    public EventAggregator eventAggregator;

    private static EventAggregatorRepository aggregatorRepository;
    private static object _lock = new object();

    public EventAggregatorRepository()
    {
        eventAggregator = new EventAggregator();
    }

    // 单例，只要一个事件聚合器
    public static EventAggregatorRepository GetInstance()
    {
        if (aggregatorRepository == null)
        {
            lock (_lock)
            {
                if (aggregatorRepository == null)
                {
                    aggregatorRepository = new EventAggregatorRepository();
                }
            }
        }
        return aggregatorRepository;
    }

}

在发送消息的控件中：

public SendMsgControlViewModel()
{
    SendMsgCommand = new RelayCommand(SendMsg);
}

private void SendMsg(object t)
{
    Student student = new Student()
    {
        Name = "梨花",
        Id = 12,
    };
    EventAggregatorRepository.GetInstance().eventAggregator.Send(student);
}

接收消息的控件中

public MainWindowViewModel()
{
	EventAggregatorRepository.GetInstance().eventAggregator.Register(ShowData);
}

private void ShowData(object obj)
{
	Student student = (Student)obj;
	Receive = student.Name;  // 需要显示的属性绑定

	MessageBox.Show(Receive);
}

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