Author: Tomas Rutkauskas

How to set the item index in a TRadioGroup without firing the OnClick event

Answer:
1   
2   procedure SetRadioItem(radiogroup: TRadioGroup; index: Integer);
3   var
4     ev: TNotifyEvent;
5   begin
6     ev := radiogroup.OnClick;
7     radiogroup.OnClick := nil;
8     radiogroup.ItemIndex := index;
9     radiogroup.Onclick := ev;
10  end;


A bit roundabout but it works. A checkbox could be treated similarly but I think 
you can also set its state by sending a BM_SETCHECK to it without having the 
OnClick event fire. This is untested:
11  
12  procedure SetCheckbox(checkbox: TCheckbox; checked: Boolean);
13  const
14    flags: array[boolean] of Integer = (BST_UNCHECKED, BST_CHECKED);
15  begin
16    checkbox.Perform(BM_SETCHECK, flags[checked], 0);
17  end;