IWiaEventCallback::ImageEventCallback method (wia_xp.h)

The IWiaEventCallback::ImageEventCallback method is invoked by the Windows Image Acquisition (WIA) run-time system when a hardware device event occurs.

Syntax

HRESULT ImageEventCallback(
  [in]      const GUID *pEventGUID,
  [in]      BSTR       bstrEventDescription,
  [in]      BSTR       bstrDeviceID,
  [in]      BSTR       bstrDeviceDescription,
  [in]      DWORD      dwDeviceType,
  [in]      BSTR       bstrFullItemName,
  [in, out] ULONG      *pulEventType,
  [in]      ULONG      ulReserved
);

Parameters

[in] pEventGUID

Type: const GUID*

Specifies the unique identifier of the event. For a complete list of device events, see WIA Event Identifiers.

[in] bstrEventDescription

Type: BSTR

Specifies the string description of the event.

[in] bstrDeviceID

Type: BSTR

Specifies the unique identifier of the WIA device.

[in] bstrDeviceDescription

Type: BSTR

Specifies the string description of the device.

[in] dwDeviceType

Type: DWORD

Specifies the type of the device. See WIA Device Type Specifiers for a list of possible values.

[in] bstrFullItemName

Type: BSTR

Specifies the full name of the WIA item that represents the device.

[in, out] pulEventType

Type: ULONG*

Pointer to a ULONG that specifies whether an event is a notification event, an action event, or both. A value of 1 indicates a notification event, a value of 2 indicates an action event, and a value of 3 indicates that the event is of both notification and action type.

[in] ulReserved

Type: ULONG

Reserved for user information.

Return value

Type: HRESULT

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

To receive notification of WIA hardware device events, applications pass a pointer to the IWiaEventCallback interface to the RegisterEventCallbackInterface method. The WIA run-time system then uses that interface pointer to invoke the IWiaEventCallback::ImageEventCallback method whenever a WIA hardware device event occurs.

Note that there is no guarantee the callback will be invoked on the same thread that registered the IWiaEventCallback interface.

Requirements