C#: What is the difference between async Task and async void in C#?

async Task — awaitable. async void — fire-and-forget (avoid!).

async Task:

• Can be awaited.
• Exceptions can be caught.
• Recommended.

1public async Task DoWorkAsync() {
2    await Task.Delay(1000);
3}
4
5// Can await
6await DoWorkAsync();
7
8// Can catch exceptions
9try {
10    await DoWorkAsync();
11} catch (Exception ex) {
12    Console.WriteLine(ex);
13}

async void:

• Cannot be awaited.
• Exceptions crash process.
• Only for event handlers.

1// Event handler (only valid use)
2private async void Button_Click(object sender, RoutedEventArgs e) {
3    await DoWorkAsync();
4}

Why async void is dangerous:

• No way to know when it completes.
• Exceptions propagate to synchronization context.
• Can crash application.