unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ComCtrls;type TForm1 = class(TForm) RichEdit1: TRichEdit;
Label1: TLabel;// RichEdit2: TRichEdit;
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject;
var Action: TCloseAction);
private { Private declarations } PRichEdWndProc, POldWndProc: Pointer;
procedure RichEdWndProc(var Msg: TMessage);
public { Public declarations } end;
var Form1: TForm1;implementation{$R *.dfm}procedure TForm1.RichEdWndProc(var Msg: TMessage);begin
Msg.Result := CallWindowProc(POldWndProc, RichEdit1.Handle, Msg.Msg, Msg.wParam, Msg.lParam);
if (Msg.Msg = WM_VSCROLL) and (LOWORD(Msg.wParam) = SB_THUMBTRACK) then
begin
Label1.Caption := 'Pos is ' + IntToStr(HIWORD(Msg.wParam));// RichEdit2.Perform(Msg.Msg, Msg.wParam, Msg.lParam);// SetScrollPos(RichEdit2.Handle, SB_VERT, HIWORD(Msg.wParam), True);
end;
end;
procedure TForm1.FormCreate(Sender: TObject);begin
PRichEdWndProc := MakeObjectInstance(RichEdWndProc);
POldWndProc := Pointer(SetWindowLong(RichEdit1.Handle, GWL_WNDPROC, Integer(PRichEdWndProc)));end;
procedure TForm1.FormClose(Sender: TObject;
var Action: TCloseAction);begin
if Assigned(PRichEdWndProc) then
begin
SetWindowLong(RichEdit1.Handle, GWL_WNDPROC, Integer(POldWndProc));
FreeObjectInstance(PRichEdWndProc);
end;
end;
end.