Author: Tomas Rutkauskas

I have a form with a page control, and each tab sheet of the page control contains 
a frame. I would like to delete the frame along with the parent tab sheet if the 
user clicks a certain button on the frame. What's the best way to do this? It seems 
that if the tab sheet's free method is called from inside the button-click event 
handler, the button will be freed before the event handler is finished executing.

Answer:

The way to solve this is do like TCustomform.Release does it: post (via 
PostMessage) a user message to the form, have the form free the component in 
response to the message.

1   const
2     UM_DESTROYCONTROL = WM_USER + 230;
3   
4     {in form declaration}
5     private
6       { Private declarations }
7   
8   procedure UmDestroyControl(var msg: TMessage); message UM_DESTROYCONTROL;
9   
10  {in the buttons OnClick handler}
11  
12  var
13    ctrl: TWinControl;
14  begin
15    ctrl := GetParentForm(Sender as TButton);
16    PostMessage(ctrl.handle, UM_DESTROYCONTROL, 0, Integer(Sender));
17    { ... }
18  
19  procedure TForm1.UmDestroyControl(var msg: TMessage);
20  begin
21    TObject(msg.lparam).Free;
22  end;