ServiceControlCodeConstants
The control codes the SCM can deliver to a running service. Used as the dwControl parameter of ITbService.ChangeState (where the service reacts to the request) and as the ControlCode parameter of Services.ControlService (where the consumer issues the request to a service running elsewhere).
The values mirror the Win32 SERVICE_CONTROL_* constants verbatim --- the vb prefix is a historical hold-over from VB6's coding conventions and does not affect the numeric values.
| Constant | Value | Description |
|---|---|---|
| vbServiceControlStop | 0x01 | Request the service stop. The standard shutdown signal --- every service should handle this in ChangeState. |
| vbServiceControlPause | 0x02 | Pause the service. Only delivered if ServiceManager.SupportsPausing is True. |
| vbServiceControlContinue | 0x03 | Resume a paused service. Paired with vbServiceControlPause. |
| vbServiceControlInterrogate | 0x04 | The SCM is asking the service to re-report its current state via ReportStatus. A bare-minimum handler can ignore it --- the SCM already has the most recent status from the previous call. |
| vbServiceControlShutdown | 0x05 | The OS is shutting down. Most services treat this identically to vbServiceControlStop. |
| vbServiceControlParamChange | 0x06 | An admin has changed the service's configuration via sc.exe config. Delivered only if the service registered SERVICE_ACCEPT_PARAMCHANGE --- currently not exposed through the package. |
| vbServiceControlNetBindAdd | 0x07 | A new network binding is available. Delivered only if SERVICE_ACCEPT_NETBINDCHANGE is accepted --- currently not exposed. |
| vbServiceControlNetBindRemove | 0x08 | A network binding has been removed. |
| vbServiceControlNetBindEnable | 0x09 | A previously disabled network binding has been enabled. |
| vbServiceControlNetBindDisable | 0x0A | A network binding has been disabled. |
| vbServiceControlDeviceEvent | 0x0B | A device-arrival / -removal event. The dwEventType and lpEventData parameters of ChangeState hold the DBT_* sub-code and DEV_BROADCAST_HDR data. Only delivered when the service has accepted SERVICE_ACCEPT_HARDWAREPROFILECHANGE. |
| vbServiceControlHardwareProfileChange | 0x0C | A hardware-profile change (laptop docking, …). |
| vbServiceControlPowerEvent | 0x0D | A system power event (suspend, resume, battery low, …). The dwEventType parameter holds the PBT_* sub-code. |
| vbServiceControlSessionChange | 0x0E | A session-change event (user logon, RDP connect / disconnect, …). The dwEventType parameter holds the WTS_* sub-code. |
| vbServiceControlPreShutdown | 0x0F | The OS is about to shut down --- sent before vbServiceControlShutdown to services that have registered for the longer pre-shutdown notification window. |
| vbServiceControlTimeChange | 0x10 | The system time has changed. |
| vbServiceControlTriggerEvent | 0x20 | A registered trigger event has fired (typically used by trigger-started services). |
| vbServiceControlLowResources | 0x60 | The service should reduce its memory / CPU footprint. |
| vbServiceControlSystemLowResources | 0x61 | The whole system is low on resources. |
Control codes in the range 128--255 are reserved for user-defined codes; pass any value in that range to Services.ControlService and the package will request the matching SERVICE_USER_DEFINED_CONTROL SCM permission. Most services only need to handle vbServiceControlStop and optionally the pause / continue pair.