Aqui está um exemplo simples de como usar a ação
//C# Event using Action delegate:
public event Action OnSomeEvent;
public event Action<string> OnSomeEventWithParameters;
// Rising the event, must check if is null:
void SomeMethod()
{
if( OnSomeEvent != null )
OnSomeEvent();
if( OnSomeEventWithParameters != null )
OnSomeEventWithParameters("some parameter");
}