Author: Jonas Bilinkevicius

I need to change the 'OnChange' event of all of my components. Can someone give me 
a starting point as to how I can go about changing this event via RTTI. I want to 
be able to pass an event name or set the event to nil.

Answer:

1   uses
2     TypInfo;
3   
4   procedure TFrmRTTIOnChange.Button1Click(Sender: TObject);
5   var
6     propInfo: PPropInfo;
7     thisEvent: TNotifyEvent;
8   begin
9     propInfo := GetPropInfo(Memo1.ClassInfo, 'OnChange');
10    if propInfo <> nil then
11    begin
12      thisEvent := Memo1AltChange;
13      SetOrdProp(Memo1, PropInfo, integer(@thisEvent));
14    end;
15  end;
16  
17  procedure TFrmRTTIOnChange.Memo1Change(Sender: TObject);
18  begin
19    Caption := 'Normal On Change';
20  end;
21  
22  procedure TFrmRTTIOnChange.Memo1AltChange(Sender: TObject);
23  begin
24    Caption := 'Alternate On Change';
25  end;