How to change the TCheckBox state without assigning an OnClick event handler

Problem/Question/Abstract:

I was wondering if there was any way to change the state of the TCheckBox control without setting off the OnClick Event Handler. If certain other properties are incorrect, I want void the state the event was set to by the Click, without setting of the event handler again.

Answer:

procedure TForm1.Button1Click(Sender: TObject);
begin
  if Button1.Tag = 0 then
  begin
    SendMessage(CheckBox1.handle, BM_SETCHECK, BST_CHECKED, 0);
    Button1.Tag := 1;
  end
  else
  begin
    SendMessage(CheckBox1.handle, BM_SETCHECK, BST_UNCHECKED, 0);
    Button1.Tag := 0;
  end;
end;

procedure TForm1.CheckBox1Click(Sender: TObject);
begin
  Showmessage('clicked');
end;