unit UMessages;
//interception des messages parvenant directement à la fenêtre d'application
interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
   Edit1: TEdit;
   Label1: TLabel;
   Label2: TLabel;
   Memo1: TMemo;
   Memo2: TMemo;
   Labelmemo1: TLabel;
   Labelmemo2: TLabel;
   Label5: TLabel;
   Label6: TLabel;
   LabelWparam: TLabel;
   LabelLparam: TLabel;
   LabelTime: TLabel;
   Label3: TLabel;
   Label4: TLabel;
   procedure FormCreate(Sender: TObject);
   procedure AppMessage(var Msg: TMsg; var Handled: Boolean);
   procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
     Shift: TShiftState; X, Y: Integer);
  private
   { Déclarations privées }
  public
   { Déclarations publiques }
  end;
  {TMSG (2.x)     (WINTYPES unit)  Aide dans TPW1.5

  TMsg = packed record
   hwnd: HWnd;
   message: Word;
   wParam: Word;
   lParam: LongInt;
   time: Longint;
   pt: TPoint;
  end;

The TMSG structure contains information from the Windows application queue.

Member    Description

hwnd    Identifies the window that receives the message.
message    Specifies the message number.
wParam    Specifies additional information about the message. The exact meaning depends on the message value.
lParam    Specifies additional information about the message. The exact meaning depends on the message value.
time    Specifies the time at which the message was posted.
pt    Specifies the position of the cursor, in screen coordinates, when the message was posted.

See Also

TEVENTMSG, GetMessage
}
var
  Form1: TForm1;

implementation
var HwndAvantPreced,HwndPrecedent:HWND;
//Utilisez Winsight en mode suivi des messages options (souris,fenêtre,système)

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
Application.OnMessage := AppMessage;
end;

procedure TForm1.AppMessage(var Msg: TMsg; var Handled: Boolean);
var infoWindow:string;
begin
if not Handled then
with Msg do
begin
  if hwnd=Form1.handle then
  memo1.lines.add(inttostr(memo1.lines.count)+'//fenêtre : '+Form1.name+'='+IntToStr(hwnd))
  else
  if hwnd=Application.handle then
  memo1.lines.add(inttostr(memo1.lines.count)+'//fenêtre : Application'+'='+IntToStr(hwnd))
  else
  begin
  if hwnd=Edit1.Handle then
   infoWindow:='Edit1'
  else
  if hwnd=memo1.Handle then
    infoWindow:='memo1'
  else
  if hwnd=memo2.Handle then
    infoWindow:='memo2';
  memo1.lines.add(inttostr(memo1.lines.count)+'//fenêtre : '
            +infoWindow+' ='+IntToStr(hwnd));
  end;
  Label6.Caption:=Label5.Caption;
  Label5.Caption:=IntToStr(hwnd);
  case message of
  WM_LBUTTONDOWN: memo2.lines.add('souris LEFT: '+IntToStr(message));
  WM_RBUTTONDOWN: memo2.lines.add('souris RIGHT: '+IntToStr(message));
  WM_KEYDOWN:memo2.lines.add('clavier KEYDOWN: '+IntToStr(message));
  end;
  LabelWparam.Caption:= 'wParam='+IntToStr(wParam);
  LabelLparam.Caption:= 'lParam='+IntToStr(lParam);
  LabelTime.Caption:= 'Time='+IntToStr(Time);
  Edit1.text := 'x='+IntToStr(pt.x)+' y='+IntToStr(pt.y)+'//Handle='+IntToStr(Edit1.Handle);
  Labelmemo1.Caption:='//Handle memo1='+IntToStr(memo1.Handle);
  Labelmemo2.Caption:='//Handle memo2='+IntToStr(memo2.Handle);
  Label1.caption:=inttostr(memo1.lines.count); //n'a pas de Handle car TGraphicControl
  Label2.caption:=inttostr(memo2.lines.count); //n'a pas de Handle car TGraphicControl
end
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
if Button=mbRight then
  memo1.Clear
end;

end.