PC Connectity with VB6

[mkintanar]

Hello all,

I plan to use the PC Connectivity Libraries in a VB6 program to monitor a Nokia 6150 connected to a server running Win NT 4. Normally I would just run the program in the foreground. However, since it will be running on an NT environment, is there an advantage to run it as an NT Service instead?

[invesa]

Hi,


I would advise you to run it as an NT service.
Otherwise your NT server would allways need to be logged on.
If you run it as a service, it doesn't matter which user logs
onto that system, and it doesn't even have to be logged on !

best regards,
Kris

[mkintanar]

Thank you for your advise, Inversa.
Would you by any chance know how to convert a VB6 program into an NT Service?

[invesa]

Put the following code in a module,
and look at which functions are available.
If you need more info, you can check it out at
http://msdn.microsoft.com

'**************************************
' Name: NT Service Module (Run EXE as Se
' rvice)
' Description:Use this modified code fro
' m the MSDN CDs to add your executable to
' the NT service list to be loaded without
' logging in! Make your EXE run in the bac
' kground and keep running even if the use
' r logs off.
'
' Inputs:InstallService : Adds Service t
' o NT List
RemoveService : Removes Service from NT
' List
RunService : Start a Service
'
' Returns:None
'
'Assumes:' Required Advanced Programming
' Skills
'
'**************************************

Option Explicit
' Put this Code in a Standard Module
' This code was taken from the MSDN CDs
' and modified
' to allow for easier use.
' MSDN Topic: INFO: Running Visual Basic
' Applications as Windows NT Services
Private Const SERVICE_WIN32_OWN_PROCESS = &H10&
Private Const SERVICE_WIN32_SHARE_PROCESS = &H20&
Private Const SERVICE_WIN32 = SERVICE_WIN32_OWN_PROCESS + SERVICE_WIN32_SHARE_PROCESS
Private Const SERVICE_ACCEPT_STOP = &H1
Private Const SERVICE_ACCEPT_PAUSE_CONTINUE = &H2
Private Const SERVICE_ACCEPT_SHUTDOWN = &H4
Private Const SC_MANAGER_CONNECT = &H1
Private Const SC_MANAGER_CREATE_SERVICE = &H2
Private Const SC_MANAGER_ENUMERATE_SERVICE = &H4
Private Const SC_MANAGER_LOCK = &H8
Private Const SC_MANAGER_QUERY_LOCK_STATUS = &H10
Private Const SC_MANAGER_MODIFY_BOOT_CONFIG = &H20
Private Const STANDARD_RIGHTS_REQUIRED = &HF0000
Private Const SERVICE_QUERY_CONFIG = &H1
Private Const SERVICE_CHANGE_CONFIG = &H2
Private Const SERVICE_QUERY_STATUS = &H4
Private Const SERVICE_ENUMERATE_DEPENDENTS = &H8
Private Const SERVICE_START = &H10
Private Const SERVICE_STOP = &H20
Private Const SERVICE_PAUSE_CONTINUE = &H40
Private Const SERVICE_INTERROGATE = &H80
Private Const SERVICE_USER_DEFINED_CONTROL = &H100
Private Const SERVICE_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED Or SERVICE_QUERY_CONFIG Or SERVICE_CHANGE_CONFIG Or SERVICE_QUERY_STATUS Or SERVICE_ENUMERATE_DEPENDENTS Or SERVICE_START Or SERVICE_STOP Or SERVICE_PAUSE_CONTINUE Or SERVICE_INTERROGATE Or SERVICE_USER_DEFINED_CONTROL)
Private Const SERVICE_DISABLED As Long = &H4
Private Const SERVICE_DEMAND_START As Long = &H3
Private Const SERVICE_AUTO_START As Long = &H2
Private Const SERVICE_SYSTEM_START As Long = &H1
Private Const SERVICE_BOOT_START As Long = &H0


Public Enum e_ServiceType
e_ServiceType_Disabled = 4
e_ServiceType_Manual = 3
e_ServiceType_Automatic = 2
e_ServiceType_SystemStart = 1
e_ServiceType_BootTime = 0
End Enum
Private Const SERVICE_ERROR_NORMAL As Long = &H1


Private Enum SERVICE_CONTROL
SERVICE_CONTROL_STOP = &H1
SERVICE_CONTROL_PAUSE = &H2
SERVICE_CONTROL_CONTINUE = &H3
SERVICE_CONTROL_INTERROGATE = &H4
SERVICE_CONTROL_SHUTDOWN = &H5
End Enum


Private Enum SERVICE_STATE
SERVICE_STOPPED = &H1
SERVICE_START_PENDING = &H2
SERVICE_STOP_PENDING = &H3
SERVICE_RUNNING = &H4
SERVICE_CONTINUE_PENDING = &H5
SERVICE_PAUSE_PENDING = &H6
SERVICE_PAUSED = &H7
End Enum


Private Type SERVICE_TABLE_ENTRY
lpServiceName As String
lpServiceProc As Long
lpServiceNameNull As Long
lpServiceProcNull As Long
End Type


Private Type SERVICE_STATUS
dwServiceType As Long
dwCurrentState As Long
dwControlsAccepted As Long
dwWin32ExitCode As Long
dwServiceSpecificExitCode As Long
dwCheckPoint As Long
dwWaitHint As Long
End Type


Private Declare Function StartServiceCtrlDispatcher Lib "advapi32.dll" Alias "StartServiceCtrlDispatcherA" (lpServiceStartTable As SERVICE_TABLE_ENTRY) As Long


Private Declare Function RegisterServiceCtrlHandler Lib "advapi32.dll" Alias "RegisterServiceCtrlHandlerA" (ByVal lpServiceName As String, ByVal lpHandlerProc As Long) As Long


Private Declare Function SetServiceStatus Lib "advapi32.dll" (ByVal hServiceStatus As Long, lpServiceStatus As SERVICE_STATUS) As Long


Private Declare Function OpenSCManager Lib "advapi32.dll" Alias "OpenSCManagerA" (ByVal lpMachineName As String, ByVal lpDatabaseName As String, ByVal dwDesiredAccess As Long) As Long


Private Declare Function CreateService Lib "advapi32.dll" Alias "CreateServiceA" (ByVal hSCManager As Long, ByVal lpServiceName As String, ByVal lpDisplayName As String, ByVal dwDesiredAccess As Long, ByVal dwServiceType As Long, ByVal dwStartType As Long, ByVal dwErrorControl As Long, ByVal lpBinaryPathName As String, ByVal lpLoadOrderGroup As String, ByVal lpdwTagId As String, ByVal lpDependencies As String, ByVal lp As String, ByVal lpPassword As String) As Long


Private Declare Function DeleteService Lib "advapi32.dll" (ByVal hService As Long) As Long


Declare Function CloseServiceHandle Lib "advapi32.dll" (ByVal hSCObject As Long) As Long


Declare Function OpenService Lib "advapi32.dll" Alias "OpenServiceA" (ByVal hSCManager As Long, ByVal lpServiceName As String, ByVal dwDesiredAccess As Long) As Long
Private hServiceStatus As Long
Private ServiceStatus As SERVICE_STATUS
Dim SERVICE_NAME As String


Public Sub InstallService(serviceName As String, serviceType As e_ServiceType)
Dim hSCManager As Long
Dim hService As Long
Dim cmd As String
Dim lServiceType As Long

Private Const SERVICE_DISABLED As Long = &H4
Private Const SERVICE_DEMAND_START As Long = &H3
Private Const SERVICE_AUTO_START As Long = &H2
Private Const SERVICE_SYSTEM_START As Long = &H1
Private Const SERVICE_BOOT_START As Long = &H0



Select Case serviceType
Case e_ServiceType_Automatic
lServiceType = SERVICE_AUTO_START
Case e_ServiceType_BootTime
lServiceType = SERVICE_BOOT_START
Case e_ServiceType_Disabled
lServiceType = SERVICE_DISABLED
Case e_ServiceType_Manual
lServiceType = SERVICE_DEMAND_START
Case e_ServiceType_SystemStart
lServiceType = SERVICE_SYSTEM_START
End Select

hSCManager = OpenSCManager(vbNullString, vbNullString, SC_MANAGER_CREATE_SERVICE)
hService = CreateService(hSCManager, serviceName, serviceName, SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS, lServiceType, SERVICE_ERROR_NORMAL, App.Path & "\" & App.EXEName, vbNullString, vbNullString, vbNullString, vbNullString, vbNullString)
CloseServiceHandle hService
CloseServiceHandle hSCManager
End Sub


Public Sub RemoveService(serviceName As String)
Dim hSCManager As Long
Dim hService As Long
Dim cmd As String
hSCManager = OpenSCManager(vbNullString, vbNullString, SC_MANAGER_CREATE_SERVICE)
hService = OpenService(hSCManager, serviceName, SERVICE_ALL_ACCESS)
DeleteService hService
CloseServiceHandle hService
CloseServiceHandle hSCManager
End Sub


Public Function RunService(serviceName As String) As Boolean
Dim ServiceTableEntry As SERVICE_TABLE_ENTRY
Dim b As Boolean
ServiceTableEntry.lpServiceName = serviceName
SERVICE_NAME = serviceName
ServiceTableEntry.lpServiceProc = FncPtr(AddressOf ServiceMain)
b = StartServiceCtrlDispatcher(ServiceTableEntry)
RunService = b
End Function


Private Sub ServiceMain(ByVal dwArgc As Long, ByVal lpszArgv As Long)
Dim b As Boolean
'Set initial state
ServiceStatus.dwServiceType = SERVICE_WIN32_OWN_PROCESS
ServiceStatus.dwCurrentState = SERVICE_START_PENDING
ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP Or SERVICE_ACCEPT_PAUSE_CONTINUE Or SERVICE_ACCEPT_SHUTDOWN
ServiceStatus.dwWin32ExitCode = 0
ServiceStatus.dwServiceSpecificExitCode = 0
ServiceStatus.dwCheckPoint = 0
ServiceStatus.dwWaitHint = 0
hServiceStatus = RegisterServiceCtrlHandler(SERVICE_NAME, AddressOf Handler)
ServiceStatus.dwCurrentState = SERVICE_START_PENDING
b = SetServiceStatus(hServiceStatus, ServiceStatus)
ServiceStatus.dwCurrentState = SERVICE_RUNNING
b = SetServiceStatus(hServiceStatus, ServiceStatus)
End Sub


Private Sub Handler(ByVal fdwControl As Long)
Dim b As Boolean



Select Case fdwControl
Case SERVICE_CONTROL_PAUSE
ServiceStatus.dwCurrentState = SERVICE_PAUSED
Case SERVICE_CONTROL_CONTINUE
ServiceStatus.dwCurrentState = SERVICE_RUNNING
Case SERVICE_CONTROL_STOP
ServiceStatus.dwWin32ExitCode = 0
ServiceStatus.dwCurrentState = SERVICE_STOP_PENDING
ServiceStatus.dwCheckPoint = 0
ServiceStatus.dwWaitHint = 0
b = SetServiceStatus(hServiceStatus, ServiceStatus)
ServiceStatus.dwCurrentState = SERVICE_STOPPED
Case SERVICE_CONTROL_INTERROGATE
Case Else
End Select
b = SetServiceStatus(hServiceStatus, ServiceStatus)
End Sub


Function FncPtr(ByVal fnp As Long) As Long
FncPtr = fnp
End Function




best regards,
Kris

[mkintanar]

Thanks a lot, Kris. Will try this immediately..

[mkintanar]

Hello Kris,

I just got an update from my manager that the NT 4 server where I intend to run the NOKIA monitoring VB program will be upgraded to run on Win2000 soon. Is this going to change anything? How is going to affect the 'NT Service' code fragment you gave?