how to determine which event calls procedure in delphi

Question

I have a procedure named XYZ(sender:TObject) in delphi. There is one button on my form.

Button.onclick:= xyz;
Button.OnExit:= xyz;

Both the events calls the same procedure. I want to determine in procedure XYZ, which event calls this(onclick or onexit) and according to that proceed with coding. How to determine which event gets fired? thanks

If you have such needs, probably you have too much code in xyz. You should split it, in x, y e z. Probably OnClick will call x, OnExit will call y, and both will call z. — Mad Hatter
The more general question is: How can I get a "call stack" in Delphi? - see this question Need a way to periodically log the call stack/stack trace for EVERY method/procedure/function called — mjn
@mjn That wouldn't really help here. Surely you don't won't to encode VCL private implementation details into VCL client code? — David Heffernan
@David of course your answer is the way to go - call stack parsing would be the least acceptable solution, I would not dare posting it as an answer ;) — mjn
This sound like broken logic of code reuse. Call stack is more debugging tool rather than design tool. — OnTheFly

David Heffernan David Heffernan · Accepted Answer · 2012-01-09T09:27:03

You can't get hold of that information by fair means. The solution is to use two separate top-level event handlers which in turn can call another method passing a parameter identifying which event is being handled.

type
  TButtonEventType = (beOnClick, beOnExit);

procedure TMyForm.ButtonClick(Sender: TObject);
begin
  HandleButtenEvent(beOnClick);
end;

procedure TMyForm.ButtonExit(Sender: TObject);
begin
  HandleButtenEvent(beOnExit);
end;

procedure TMyForm.HandleButtonEvent(EventType: TButtonEventType);
begin
  //use EventType to decide how to handle this
end;

how to determine which event calls procedure in delphi

1 Answers