Question

I’ve got a pretty big setup form which I’d like to populate with data from a class. so I’m doing a lot of

Edt1.text := ASettings.FirstThing; 

I’d like to avoid

Edt1.onchange := nil;
Edt1.text := ASettings.FirstThing; 
Edt1.onchange := edt1Onchange;

How do I change the text in a text box and sidestep the onchange event.

Answer 1

I have used something like changing the OnChange handler, but more often, I use a flag.

updatingFromCode := true;
Edt1.Text := ASettings.FirstThing;
updatingFromCode := false;

then

procedure TForm1.OnChange(...);
begin
  if updatingFromCode then
    Exit;
  ...

Also, rather than hardcoding the OnChange the the actual OnChange procedure, I would store the Edit control’s current value, then reset it (which will work if it is not set, or if another place has changed it, etc.)

oldOnChange := Edt1.OnChange;
Edt1.OnChange := nil;
Edt1.Text := ASettings.FirstThing; 
Edt1.OnChange := oldOnChange;