public class EventManager
{
public static void Subscribe(ViewModelBase reciever, string key, Action action)
{
EventHolder newEventHolder = new EventHolder(reciever, action);
var eventHoldersForEventId = Singleton<List<KeyValuePair<string, List>>>>.Instance;
if (eventHoldersForEventId.Any(x => x.Key == key))
{
var keyValuePair = eventHoldersForEventId.First(x => x.Key == key);
var eventHolder = keyValuePair.Value.FirstOrDefault(x => x.ViewModel.ToString() == reciever.ToString() && x.InvokeEvent == action);
if (eventHolder == default(EventHolder))
keyValuePair.Value.Add(new EventHolder(reciever, action));
}
else
{
eventHoldersForEventId.Add(new KeyValuePair<string, List>>(key, new List>()));
var KeyValuePair = eventHoldersForEventId.First(x => x.Key == key);
KeyValuePair.Value.Add(newEventHolder);
}
}
public static void Publish(string key, T data)
{
var eventHoldersForEventId = Singleton<List<KeyValuePair<string, List>>>>.Instance;
if (eventHoldersForEventId.Any(x => x.Key == key))
{
var keyValuePair = eventHoldersForEventId.First(x => x.Key == key);
var eventHolderCollection = keyValuePair.Value;
eventHolderCollection.ForEach(x => x.InvokeEvent.Invoke(data));
}
}
}
The objects that are interested in listening to events can register themselves using a Subscribe method.
The subscribe method needs an instance of the object and a delegate to invoke when the event occurs.
Publish method is used by objects to notify an event.
public class EventHolder
{
public EventHolder(ViewModelBase viewModel, Action action)
{
ViewModel = viewModel;
InvokeEvent = action;
}
public ViewModelBase ViewModel { get; private set; }
public Action InvokeEvent { get; private set; }
}
public class EventHolder
{
public EventHolder(ViewModelBase viewModel, Action action)
{
ViewModel = viewModel;
InvokeEvent = action;
}
public ViewModelBase ViewModel { get; private set; }
public Action InvokeEvent { get; private set; }
}
}
Events can be registered or subscribed by using
private void SubscribeToEvent()
{
//TargetMessenger.Subscribe(this, (x) => _projectId = x);
EventManager.Subscribe<int>(this, EventTopics.PUBLISH_PROJECTID_TO_MANAGEUSER, (data) =>
{
_projectId = data;
});
}
Event publication is done as
EventManager.Publish<int>(EventTopics.PUBLISH_PROJECTID_TO_MANAGEUSER, projectId);
Singleton is a generic class for creating singleton objects
public class Singleton where T : new()
{
Singleton() { }
public static T Instance
{
get
{
if(_initializer == default(Lazy)) _initializer = new Lazy();
return _initializer.Value;
}
}
static Lazy _initializer = default(Lazy);
}
