Question

I currently have 2 WinForms.

FormA creates an instance of FormB. I call the ShowDialog() method of FormB.

FormB defines public event Action<SomeClass, string> Analyze

When I click the ProcessEvent button of FormB I do the following:

Action<SomeClass, string> tempAction = Analyze;
if (tempAction != null)
{
  tempAction.Invoke(instanceOfSomeClass, someString);
}

But the event is not invoked because tempAction is null.

Why would it be null?

I define events in the same way in FormA and they work fine.

EDIT:

I have a presenter class that subscribes to the event:

formBInstance.Analyze += StartAnalyze

Answer 1

you must sign for event. If there is no subsribers Analyze will be null

FormB form = new FormB();
form.Analyze += OnAnanlyze; // define callback function