EventHandler type with no event args

Question

When we want to pass data to an event subscriber, we use EventArgs (or CustomEventArgs) for this.

.Net provides a build in type EventHandler that uses as a parameter an instance of EventArgs class that is build in as well.

What about cases, when I need to notify a subscriber that some action is over, for example search is over? I don't want to even use EventArgs, that won't contain anything.

Is there a build in type for signaling another class, without the need to use empty EventArgs?

Answer 1

I really would advise you to use the standard EventHandler pattern here and just pass EventArgs.Empty. However, you can use Action as an event type if you really want – it is just unusual.

Answer 2

Use Actions (below answer copied from https://stackoverflow.com/a/1689341/1288473):

Declaring:

public event Action EventWithoutParams; 
public event Action<int> EventWithIntParam;

Calling:

EventWithoutParams?.Invoke(); 
EventWithIntParam?.Invoke(123);