ISensorClassExtension::PostStateChange method (sensorsclassextension.h)

The ISensorClassExtension::PostStateChange method notifies the sensor class extension about a change in the operational state of the sensor.

Syntax

HRESULT PostStateChange(
  [in] LPWSTR      pwszSensorID,
  [in] SensorState state
);

Parameters

[in] pwszSensorID

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

[in] state

SensorState value that indicates the new state.

Return value

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

Remarks

Sensor state information is also available through the SENSOR_PROPERTY_STATE property key.

Examples

The following example code demonstrates a function that posts a state-changed event.

HRESULT PostStateEvent()
{
    // Validate that we have a pointer to the class extension.
    HRESULT hr = (NULL == m_spSensorCXT) ? E_UNEXPECTED : S_OK ;

    if (SUCCEEDED(hr))
    {
        SensorState st;

        // Retrieve the sensor state
        hr = m_pDdi->GetSensorState(&st);

        if (SUCCEEDED(hr))
        {
            // Post the state change event.
            hr = m_spSensorCXT->PostStateChange(g_wszSensorID, st);
        }
    }

    return hr;
}

Requirements

See also

• ISensorClassExtension
• ISensorDriver::OnClientSubscribeToEvents
• ISensorDriver::OnClientUnsubscribeFromEvents