How to switch users?

[alexvornads]

How to switch from users A to user B in visual basic?
User A should not log off.
Please help.

[Andy_P]

[EDIT]


This link may have some info?
http://support.microsoft.com/?kbid=841291

[alexvornads]

I use this code that i found on the page of the link you gave to me, but it does nothing

Please help!!!

Imports System.Runtime.InteropServices

Public Class Form1
    'Constant declarations that you can use for message processing follow:
    '
    Private Const _WIN32_WINNT As Int32 = &H501
    Private Const NOTIFY_FOR_THIS_SESSION As Int32 = &H0
    Private Const WM_WTSSESSION_CHANGE As Int32 = &H2B1
    Private Const WTS_CONSOLE_CONNECT As Int32 = &H1
    Private Const WTS_CONSOLE_DISCONNECT As Int32 = &H2
    Private Const WTS_SESSION_LOCK As Int32 = &H7
    Private Const WTS_SESSION_UNLOCK As Int32 = &H8
    Private Const WM_DESTROY As Int32 = &H2
    Private Const WM_ACTIVATEAPP As Int32 = &H1C
    
    'Declaration of API functions that you can use for message processing follow:
    '
    'The WTSUnRegisterSessionNotification function unregisters the specified 
    'window so that the specified window receives no more session-change notifications.
    <DllImport("Wtsapi32.dll")> _
    Private Shared Function WTSUnRegisterSessionNotification( _
    ByVal hWnd As IntPtr) As Boolean

    End Function
    'The WTSRegisterSessionNotification function registers the specified 
    'window to receive session-change notifications.
    <DllImport("Wtsapi32.dll")> _
    Private Shared Function WTSRegisterSessionNotification( _
    ByVal hWnd As IntPtr, ByVal dwFlags As Int32) As Boolean

    End Function
    'The PostQuitMessage function indicates to the system that a thread 
    'has made a request to quit. The PostQuitMessage function is typically used in 
    'response to a WM_DESTROY message.
    <DllImport("user32.dll")> _
    Private Shared Sub PostQuitMessage( _
    ByVal nExitCode As Int32)

    End Sub
    'The OpenIcon function restores a minimized (iconic) window to its 
    'previous size and previous position. The OpenIcon function then activates the window. 
    <DllImport("user32.dll")> _
    Private Shared Function OpenIcon(ByVal hwnd As IntPtr) As Boolean

    End Function
    'The SetForegroundWindow function puts the thread that created the 
    'specified window in the foreground and then activates the window.
    <DllImport("user32.dll")> _
    Private Shared Function SetForegroundWindow(ByVal hwnd As IntPtr) As Boolean

    End Function
   




    '
    'The following processes Windows messages:
    '
    <System.Security.Permissions.PermissionSetAttribute _
    (System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
    Protected Overrides Sub WndProc(ByRef m As Message)        '
        Select Case (m.Msg)
            '
            Case WM_WTSSESSION_CHANGE

                Select Case (m.WParam.ToInt32)
                    Case WTS_CONSOLE_CONNECT
                        MessageBox.Show("WTS_CONSOLE_CONNECT", "WM_SESSION_CHANGE", MessageBoxButtons.OK)
                    Case WTS_CONSOLE_DISCONNECT
                        MessageBox.Show("WTS_CONSOLE_DISCONNECT", "WM_SESSION_CHANGE", MessageBoxButtons.OK)
                    Case WTS_SESSION_LOCK
                        MessageBox.Show("WTS_SESSION_LOCK", "WM_SESSION_CHANGE", MessageBoxButtons.OK)
                    Case WTS_SESSION_UNLOCK
                        MessageBox.Show("WTS_SESSION_UNLOCK", "WM_SESSION_CHANGE", MessageBoxButtons.OK)
                    Case Else
                        MessageBox.Show("test", "test", MessageBoxButtons.OK)
                End Select
                '               
        End Select
        '
        MyBase.WndProc(m)
        '
    End Sub
    '
    Protected Overrides Sub OnHandleCreated(ByVal e As System.EventArgs)
        '
        'The WTSRegisterSessionNotification function registers the specified
        'window to receive session-change notifications.
        '
        WTSRegisterSessionNotification(Me.Handle, NOTIFY_FOR_THIS_SESSION)
        '
        MyBase.OnHandleCreated(e)
        '
    End Sub
    '
    Protected Overrides Sub OnHandleDestroyed(ByVal e As System.EventArgs)
        '
        WTSUnRegisterSessionNotification(Me.Handle)
        PostQuitMessage(0)
        '
    End Sub
    '







    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
        '
        Dim blnChk As Boolean
        '
        'Checking for the existence of an
        'application that is already running.
        '
        If UBound(Diagnostics.Process.GetProcessesByName _
        (Diagnostics.Process.GetCurrentProcess.ProcessName)) > 0 Then
            '
            'Checking if there is already
            'an instance that is running in this user's session.
            '
            blnChk = ActivatePrevInstance("FastSwitchingForm")
            '
            If (blnChk = False) Then
                MsgBox("Another instance of " & _
                Diagnostics.Process.GetCurrentProcess.ProcessName & _
                " is already running in another user's session on this computer." & _
                " You cannot run two instances at a time. You must use the other instance.")
                End
            End If
            '
        End If
        '
    End Sub

    '
    'This is a function to verify whether the application is already running.
    'If the application is already running, set the focus on the application.
    '
    Private Function ActivatePrevInstance(ByVal argStrAppToFind As String) As Boolean
        '
        Dim PrevHndl As IntPtr = Nothing
        Dim result As Boolean
        Dim objProcess As New Process() 'This is a variable to hold an individual process.
        Dim objProcesses() As Process 'This is a collection of all the processes that are running on the local computer.
        '
        objProcesses = Process.GetProcesses() 'Get all processes into the collection.()
        '
        For Each objProcess In objProcesses
            '
            'Check and then exit if there is an application that is already running.
            '
            If UCase(objProcess.MainWindowTitle) = UCase(argStrAppToFind) Then
                MsgBox("Another instance of " & argStrAppToFind & _
                " is already running on this computer. " & _
                "You cannot run two instances at a time." & _
                " You must use the other instance.")
                PrevHndl = objProcess.MainWindowHandle
                Exit For
            End If
        Next
        '
        If PrevHndl.Equals(IntPtr.Zero) Then
            ActivatePrevInstance = False
            Exit Function 'If no previous instance is found, exit the application.
        Else
            ActivatePrevInstance = True
        End If
        '
        result = OpenIcon(PrevHndl) 'Restore the program.
        result = SetForegroundWindow(PrevHndl) 'Activate the application.
        End 'End the current instance of the application.
        '
    End Function
    '



End Class

[alexvornads]

can anybody help me?