public static async Task NullableInvokeAsync <T>(this AsyncEvent <T> asyncEvent,
object sender, T eventArgs)
{
if (asyncEvent != null)
{
await asyncEvent.InvokeAsync(sender, eventArgs);
}
}
public async Task <T> Await(CancellationToken cancellationToken)
{
try
{
await _completionSource.Task
.WithCancellation(cancellationToken)
.ConfigureAwait(false);
}
finally
{
_asyncEvent -= SubscriptionHandler;
}
return(_completionSource.Task.Result);
}
public static AsyncEvent <TEventArgs> operator +(
AsyncEvent <TEventArgs> e, Func <object, TEventArgs, Task> callback)
{
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
//Note: Thread safety issue- if two threads register to the same event (on the first time, i.e when it is null)
//they could get a different instance, so whoever was first will be overridden.
//A solution for that would be to switch to a public constructor and use it, but then we'll 'lose' the similar syntax to c# events
if (e == null)
{
e = new AsyncEvent <TEventArgs>();
}
lock (e._locker)
{
e._invocationList.Add(callback);
}
return(e);
}
public AsyncEventAwaiter(ref AsyncEvent <T> asyncEvent)
{
asyncEvent += SubscriptionHandler;
_asyncEvent = asyncEvent;
_completionSource = new TaskCompletionSource <T>();
}
