Why doesn't await on Task.WhenAll throw an AggregateException?

Question

In this code:

private async void button1_Click(object sender, EventArgs e) {
    try {
        await Task.WhenAll(DoLongThingAsyncEx1(), DoLongThingAsyncEx2(         


        

Answer 1

You're thinking of Task.WaitAll - it throws an AggregateException.

WhenAll just throws the first exception of the list of exceptions it encounters.