/// <summary>
/// Subscribes the given action to the given event/selection type. Since the eventType is determined at runtime, the event/selection arguments are not available :
/// you can just subscribe a parameterless action.
/// </summary>
/// <param name="eventAggregator">The event aggregator instance from which to resolve the event.</param>
/// <param name="eventType">The type of the event/selection to which the subscription is made. Supported types are types that extend CompositePresentationEvent or SelectionBase.</param>
/// <param name="action">The action that is to be invoked when the specified event is fired / the specified selection changes.</param>
/// <param name="threadOption">The thread on which the event should be handled.</param>
/// <param name="keepSubscriberReferenceAlive">A flag indicating if a reference to the subscription should be held or not.</param>
public static SubscriptionToken Subscribe(this IEventAggregator eventAggregator, Type eventType, Action action, ThreadOption threadOption = ThreadOption.PublisherThread, bool keepSubscriberReferenceAlive = true)
{
eventAggregator.AssertNotNull(nameof(eventAggregator));
eventType.AssertParameterNotNull(nameof(eventType));
action.AssertParameterNotNull(nameof(action));
if (eventType.IsSubclassOfRawGeneric(typeof(CompositePresentationEvent <>)))
{
var payloadType = eventType.GetBaseTypeGenericArgument(typeof(CompositePresentationEvent <>));
var subscriptionMethod = typeof(EventAggregatorHelpers).GetMethod(nameof(EventAggregatorHelpers.SubscribeToEvent)).MakeGenericMethod(new Type[] { eventType, payloadType });
return((SubscriptionToken)subscriptionMethod.Invoke(null, new object[] { eventAggregator, threadOption, keepSubscriberReferenceAlive, action }));
}
else if (eventType.IsSubclassOfRawGeneric(typeof(SelectionBase <>)))
{
var payloadType = eventType.GetBaseTypeGenericArgument(typeof(SelectionBase <>));
var subscriptionMethod = typeof(EventAggregatorHelpers).GetMethod(nameof(EventAggregatorHelpers.SubscribeToSelection)).MakeGenericMethod(new Type[] { eventType, payloadType });
return((SubscriptionToken)subscriptionMethod.Invoke(null, new object[] { eventAggregator, threadOption, keepSubscriberReferenceAlive, action }));
}
else
{
throw new NotSupportedException($"{eventType.Name} is not a supported event type. Supported event types are types which extend CompositePresentationEvent or SelectionBase.");
}
}
/// <summary>
/// Returns the instance of the specified event type (from the container), performing a registration check first.
/// It is the equivalent of EventAggregator.GetEvent'1, but this can be called on runtime.
/// </summary>
/// <param name="eventAggregator">The event aggregator instance from which to resolve the event.</param>
/// <param name="eventType">The type of the event that is to be resolved. Supported types are types that extend CompositePresentationEvent or SelectionBase.</param>
/// <returns></returns>
public static EventBase GetEvent(this IEventAggregator eventAggregator, Type eventType)
{
eventAggregator.AssertNotNull(nameof(eventAggregator));
eventType.AssertParameterNotNull(nameof(eventType));
if (!(eventType.IsSubclassOfRawGeneric(typeof(CompositePresentationEvent <>)) ||
eventType.IsSubclassOfRawGeneric(typeof(SelectionBase <>))))
{
throw new NotSupportedException($"Error : {eventType.Name} is not a supported eventType. Supported types are either subtypes of CompositePresentationEvent<T> (events) or " +
$"subtypes of SelectionBase<T>(selections).");
}
var eventGetter = typeof(IEventAggregator).GetMethod(nameof(eventAggregator.GetEvent)).MakeGenericMethod(eventType);
return((EventBase)eventGetter.Invoke(eventAggregator, new object[] { }));
}