Как узнать о переключении сессии

Code:

unit Wtsapi;

interface

{ (c) By Thomas Stutz 10. April 02 }

uses

Windows;

const

// The WM_WTSSESSION_CHANGE message notifies applications of changes in session state.

WM_WTSSESSION_CHANGE = $2B1;

// wParam values:

WTS_CONSOLE_CONNECT = 1;

WTS_CONSOLE_DISCONNECT = 2;

WTS_REMOTE_CONNECT = 3;

WTS_REMOTE_DISCONNECT = 4;

WTS_SESSION_LOGON = 5;

WTS_SESSION_LOGOFF = 6;

WTS_SESSION_LOCK = 7;

WTS_SESSION_UNLOCK = 8;

WTS_SESSION_REMOTE_CONTROL = 9;

// Only session notifications involving the session attached to by the window

// identified by the hWnd parameter value are to be received.

NOTIFY_FOR_THIS_SESSION = 0;

// All session notifications are to be received.

NOTIFY_FOR_ALL_SESSIONS = 1;

function RegisterSessionNotification(Wnd: HWND; dwFlags: DWORD): Boolean;

function UnRegisterSessionNotification(Wnd: HWND): Boolean;

function GetCurrentSessionID: Integer;

implementation

function RegisterSessionNotification(Wnd: HWND; dwFlags: DWORD): Boolean;

// The RegisterSessionNotification function registers the specified window

// to receive session change notifications.

// Parameters:

// hWnd: Handle of the window to receive session change notifications.

// dwFlags: Specifies which session notifications are to be received:

// (NOTIFY_FOR_THIS_SESSION, NOTIFY_FOR_ALL_SESSIONS)

type

TWTSRegisterSessionNotification = function(Wnd: HWND; dwFlags: DWORD): BOOL; stdcall;

var

hWTSapi32dll: THandle;

WTSRegisterSessionNotification: TWTSRegisterSessionNotification;

begin

Result := False;

hWTSAPI32DLL := LoadLibrary('Wtsapi32.dll');

if (hWTSAPI32DLL > 0) then

begin

   try @WTSRegisterSessionNotification :=

       GetProcAddress(hWTSAPI32DLL, 'WTSRegisterSessionNotification');

     if Assigned(WTSRegisterSessionNotification) then

     begin

       Result:= WTSRegisterSessionNotification(Wnd, dwFlags);

     end;

   finally

     if hWTSAPI32DLL > 0 then

       FreeLibrary(hWTSAPI32DLL);

   end;

end;

end;

function UnRegisterSessionNotification(Wnd: HWND): Boolean;

// The RegisterSessionNotification function unregisters the specified window

// Parameters:

// hWnd: Handle to the window

type

TWTSUnRegisterSessionNotification = function(Wnd: HWND): BOOL; stdcall;

var

hWTSapi32dll: THandle;

WTSUnRegisterSessionNotification: TWTSUnRegisterSessionNotification;

begin

Result := False;

hWTSAPI32DLL := LoadLibrary('Wtsapi32.dll');

if (hWTSAPI32DLL > 0) then

begin

   try @WTSUnRegisterSessionNotification :=

       GetProcAddress(hWTSAPI32DLL, 'WTSUnRegisterSessionNotification');

     if Assigned(WTSUnRegisterSessionNotification) then

     begin

       Result:= WTSUnRegisterSessionNotification(Wnd);

     end;

   finally

     if hWTSAPI32DLL > 0 then

       FreeLibrary(hWTSAPI32DLL);

   end;

end;

end;

function GetCurrentSessionID: Integer;

// Getting the session id from the current process

type

TProcessIdToSessionId = function(dwProcessId: DWORD; pSessionId: DWORD): BOOL; stdcall;

var

ProcessIdToSessionId: TProcessIdToSessionId;

hWTSapi32dll: THandle;

Lib : THandle;

pSessionId : DWord;

begin

Result := 0;

Lib := GetModuleHandle('kernel32');

if Lib <> 0 then

begin

   ProcessIdToSessionId := GetProcAddress(Lib, '1ProcessIdToSessionId');

   if Assigned(ProcessIdToSessionId) then

   begin

     ProcessIdToSessionId(GetCurrentProcessId(), DWORD(@pSessionId));

     Result:= pSessionId;

   end;

end;

end;

end.

Code:

unit Unit1;

interface

uses

Windows, Messages, {...},  Wtsapi;

type

TForm1 = class(TForm)

   procedure FormCreate(Sender: TObject);

   procedure FormDestroy(Sender: TObject);

private

{ Private declarations }

   FRegisteredSessionNotification : Boolean;

   procedure AppMessage(var Msg: TMSG; var HAndled: Boolean);

end;

var

Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.AppMessage(var Msg: TMSG; var Handled: Boolean);

var

strReason: string;

begin

Handled := False;

// Check for WM_WTSSESSION_CHANGE message

if Msg.Message = WM_WTSSESSION_CHANGE then

begin

    case Msg.wParam of

      WTS_CONSOLE_CONNECT:

          strReason := 'WTS_CONSOLE_CONNECT';

      WTS_CONSOLE_DISCONNECT:

          strReason := 'WTS_CONSOLE_DISCONNECT';

      WTS_REMOTE_CONNECT:

          strReason := 'WTS_REMOTE_CONNECT';

      WTS_REMOTE_DISCONNECT:

          strReason := 'WTS_REMOTE_DISCONNECT';

      WTS_SESSION_LOGON:

          strReason := 'WTS_SESSION_LOGON';

      WTS_SESSION_LOGOFF:

          strReason := 'WTS_SESSION_LOGOFF';

      WTS_SESSION_LOCK:

          strReason := 'WTS_SESSION_LOCK';

      WTS_SESSION_UNLOCK:

          strReason := 'WTS_SESSION_UNLOCK';

      WTS_SESSION_REMOTE_CONTROL:

          begin

            strReason := 'WTS_SESSION_REMOTE_CONTROL';

            // GetSystemMetrics(SM_REMOTECONTROL);

          end;

     else

       strReason := 'WTS_Unknown';

    end;

  // Write strReason to a Memo

  Memo1.Lines.Add(strReason + ' ' + IntToStr(msg.Lparam));

end;

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

// register the window to receive session change notifications.

FRegisteredSessionNotification := RegisterSessionNotification(Handle, NOTIFY_FOR_THIS_SESSION);

Application.OnMessage := AppMessage;

end;

procedure TForm1.FormDestroy(Sender: TObject);

begin

// unregister session change notifications.

if FRegisteredSessionNotification then

  UnRegisterSessionNotification(Handle);

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

// retrieve current session ID

ShowMessage(Inttostr(GetCurrentSessionID));

end;