1. 일반적으로 메세지 가로채기를 하려면 WinProc에 콜백을 걸어서 하는데
var
Form1: TForm1; OldWindProc: Integer;
implementation
{$R *.dfm}
function NewWinProc(hWnd:HWND;Msg:Integer;wParam:Integer;lParam:Integer):LONGINT; StdCall;
var rect: TRect;
begin
case Msg of
WM_SIZE : begin
GetClientRect(hWnd, rect); with rect do Form1.lst1.Items.Add('left:'
+IntToStr(Left)+'top:' +IntToStr(Top)+'right:'+IntToStr(rect)
+'bottom:'+IntToStr(rect));
Form1.lst1.ItemIndex := Form1.lst1.Items.Count + 1; end; end;
Result:=CallWindowProc(Pointer(OldWindProc),hWnd,Msg,wParam,lParam)
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
OldWindProc:=SetWindowLong(Form1.handle,GWL_WNDPROC,LongInt(@NewWinProc));
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
SetWindowLong(Form1.handle, GWL_WNDPROC, OldWindProc);
end;
2. 클래스 내부에 포함 할때는 다른 방법으로 합니다. 아래와 같이 글로벌 영역에서는unit Unit1;
interface
uses
Windows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls;
type
TForm1 = class(TForm)
lst1: TListBox;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
FTargetWnd: THandle; //서브클래싱 할 핸들 보관
FOldProc: Pointer; //원본 윈도우프로시져 보관
FNewProc: Pointer; //재구성 윈도우프로시져
public
procedure SubClassCreate(hWnd: THandle);
procedure SubClassWndproc(var Message: TMessage);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
// 서브 클래싱 걸기
procedure TForm1.SubClassCreate(hWnd: THandle);
begin
if FTargetWnd <> 0 then Exit;
FTargetWnd := hWnd;
FOldProc := Pointer(GetWindowLong(FTargetWnd, GWL_WNDPROC));
FNewProc := MakeObjectInstance(SubClassWndproc);
SetWindowLong(FTargetWnd, GWL_WNDPROC, LongInt(FNewProc));
end;
// 서브클래싱 윈도우프로시져 재구성
procedure TForm1.SubClassWndproc(var Message: TMessage);
begin
with Message do begin //Message 객체의 내부 메서드들로 윈도우 프로시져 원본을 돌려줌
Result:=CallWindowProc(FOldProc,FTargetWnd,Msg,WParam,LParam);
Case Msg of // Message 객체의 WM_SIZE 메세지를 받아옴
WM_SIZE : begin
lst1.Items.Add(Format('%d,%d',[LOWORD(Message.LParam),HiWord(Message.LParam)]));
lst1.ItemIndex := lst1.Items.Count - 1;
end;
end;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
//서브클래싱을 걸어 준다.예제 이므로 현재 윈도우의 핸들에
SubClassCreate(Self.Handle);
end;
//서브클래싱 해제
procedure TForm1.FormDestroy(Sender: TObject);
begin
SetWindowLong(FTargetWnd, GWL_WNDPROC, LongInt(FOldProc));
end;
end.
