System Delphi

Title: How to be notified when a session lock occurs
function WTSRegisterSessionNotification(hWnd: HWND; dwFlags: DWORD): BOOL; stdcall;
function WTSUnRegisterSessionNotification(hWND: HWND): BOOL; stdcall;
const
NOTIFY_FOR_ALL_SESSIONS = 1;
NOTIFY_FOR_THIS_SESSIONS = 0;
implementation
function WTSRegisterSessionNotification;
external 'wtsapi32.dll' Name 'WTSRegisterSessionNotification';
function WTSUnRegisterSessionNotification;
external 'wtsapi32.dll' Name 'WTSUnRegisterSessionNotification';
end.
Now the form that should be notified if the Status changed
don??t forget to ??use?? the simpleWTS-unit
unit UfrmMain;
interface
uses
{ ... everything else like Windows, SysUtils, Controls }, simpleWTS;
type
TfrmMain = class(TForm)
Label1: TLabel;
procedure FormCreate(Sender: TObject);
private
FintLockedCount: Integer; { will save how often the Workstation got locked }
procedure WndProc(var Message: TMessage); override;
{ we need our own WndProc to catch all those WTS-Messages we need }
public
end;
var
frmMain: TFrmMain;
implementation
procedure TfrmMain.WndProc(var Message: TMessage);
begin
case Message.Msg of
WM_WTSSESSION_CHANGE:
begin
if Message.wParam = WTS_SESSION_LOCK then
begin
Inc(FintLockedCount);
end;
if Message.wParam = WTS_SESSION_UNLOCK then
begin
Label1.Caption := 'Die Session wurde bereits ' +
IntToStr(FintLockedCount) + ' mal gesperrt.';
end;
end;
end;
inherited;
end;
procedure TfrmMain.FormCreate(Sender: TObject);
begin
WTSRegisterSessionNotification(Handle, NOTIFY_FOR_ALL_SESSIONS);
FintLockedCount := 0;
end;
end.