public void Detach <TViewModelEventArgs>(string dispatcher, ViewModelEventHandler <TViewModelEventArgs> callback) where TViewModelEventArgs : ViewModelEventArgs
{
// [WARNING] Reflection used. May be slow.
dispatcher = dispatcher ?? throw new ArgumentNullException("Dispatcher cannot be null.");
callback = callback ?? throw new ArgumentNullException("Callback cannot be null.");
Type ty = GetType();
EventInfo e = ty.GetEvent(dispatcher, BindingFlags.Instance | BindingFlags.Public);
if (e.MemberType != MemberTypes.Event)
{
throw new SystemException("\'" + dispatcher + "\' is not a valid dispatcher.");
}
if (e == null)
{
throw new DispatcherNotFoundException("Could not find dispatcher \'" + dispatcher + "\".");
}
if (callback.GetType() != e.EventHandlerType)
{
throw new DispatcherTypeMismatchException("Dispatcher type does not match with the callback type.");
}
e.RemoveEventHandler(this, callback);
}
/// <summary>
/// Subscribes to an <see cref="IViewModelEvent{TPayload}"/> event
/// </summary>
protected virtual void SubscribeToEvent <TEvent, TArgs>(ViewModelEventHandler <TArgs> handler)
where TEvent : class, IViewModelEvent <TArgs>, new()
{
var targetEvent = _eventDispatcher.GetEvent <TEvent>();
targetEvent.Subscribe(this, handler);
}
/// <summary>
/// Add a handler to the event.
/// </summary>
/// <param name="group">The ViewModel group.</param>
/// <param name="handler">The event handler.</param>
public virtual void Subscribe(string group, ViewModelEventHandler <TPayload> handler)
{
lock (_handlers)
{
var list = _handlers.ContainsKey(group) ? _handlers[group] : (_handlers[group] = new List <ViewModelEventHandler <TPayload> >());
list.Add(handler);
}
}
/// <summary>
/// Subscribes to an <see cref="ViewModelsGroupEvent{TPayload}"/> event
/// </summary>
protected virtual void SubscribeToGroupEvent <TEvent, TArgs>(string viewModelGroup,
ViewModelEventHandler <TArgs> handler)
where TEvent : ViewModelsGroupEvent <TArgs>, new()
{
var targetEvent = _eventDispatcher.GetEvent <TEvent>();
targetEvent.Subscribe(viewModelGroup, handler);
}
/// <summary>
/// Subscribes to an <see cref="ViewModelsGroupEvent{TPayload}"/> event
/// </summary>
protected virtual void SubscribeToGroupEvent <TEvent, TArgs>(ViewModelEventHandler <TArgs> handler)
where TEvent : ViewModelsGroupEvent <TArgs>, new()
{
if (string.IsNullOrEmpty(ViewModelGroup))
{
throw new InvalidOperationException("ViewModelGroup is not set.");
}
SubscribeToGroupEvent <TEvent, TArgs>(ViewModelGroup, handler);
}
/// <summary>
/// Remove a handler from the event.
/// </summary>
/// <param name="group">The ViewModel group.</param>
/// <param name="handler">The event handler.</param>
public virtual void Unsubscribe(string group, ViewModelEventHandler <TPayload> handler)
{
lock (_handlers)
{
if (_handlers.ContainsKey(group))
{
_handlers[group].Remove(handler);
}
}
}