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ISensorClassExtension::PostEvent method (sensorsclassextension.h)

  • Article

The ISensorClassExtension::PostEvent method raises one or more driver events in the sensor class extension.

Syntax

HRESULT PostEvent(
  LPWSTR                          pwszSensorID,
  IPortableDeviceValuesCollection *pEventCollection
);

Parameters

pwszSensorID

LPWSTR that contains the ID for the sensor for which the driver is raising the event.

pEventCollection

Pointer to an IPortableDeviceValuesCollection interface that contains the list of events being posted and their associated data.

Return value

This method returns an HRESULT. Possible values include, but are not limited to, one of the following values.

Return code Description
S_OK The method succeeded.
S_FALSE The method succeeded, but no client programs are currently subscribed to events. Do not post events when no clients are subscribed.
E_INVALIDARG The event collection was empty.
E_POINTER A required pointer argument was NULL.
HRESULT_FROM_WIN32(ERROR_CAN_NOT_COMPLETE) The class extension is not initialized.
HRESULT_FROM_WIN32(ERROR_INTERNAL_DB_CORRUPTION A serialization error occurred.
HRESULT_FROM_WIN32(ERROR_OBJECT_NOT_FOUND) No client programs are currently subscribed to events. Do not post events when no clients are subscribed.

Remarks

The sensor class extension forwards these events to the Sensor API and Location API, which in turn, raise events in client programs.

The collection passed through pEventCollection can contain one or more events. Represent each event and its associated data by using one IPortableDeviceValues object. Platform-defined PROPERTYKEYs for events and data types are defined in sensors.h.

Each IPortableDeviceValues object returned by this method must contain a time stamp, as described in SENSOR_CATEGORY_ALL.

The sensor class extension is responsible for freeing any PROPVARIANT structures provided by this method.

To specify the event type, use the SENSOR_EVENT_PARAMETER_EVENT_ID PROPERTYKEY with the appropriate GUID value.

For an example of a class that creates an event thread, see Raising sensor events

IPortableDeviceValues and IPortableDeviceValuesCollection are documented in Windows Portable Devices.

Note  The sensor class extension will call PropVariantClear for PROPVARIANTs that you pass to the sensor class extension.
 
Raise state change events by calling ISensorClassExtension::PostStateChange.

Requirements

Requirement Value
Target Platform Windows
Header sensorsclassextension.h
Library SensorsClassExtension.lib

See also

ISensorClassExtension