Windows Driver Kit: Windows Portable Devices
WPD_COMMAND_OBJECT_PROPERTIES_BULK_GET_VALUES_BY_OBJECT_FORMAT_START Command
Initializes a bulk request for multiple property values from multiple objects, filtered by object format. The driver must return a context ID to identify the bulk operation. This will be referenced in subsequent WPD_COMMAND_OBJECT_PROPERTIES_BULK_GET_VALUES_BY_OBJECT_FORMAT_NEXT calls.
Command category
WPD_CATEGORY_OBJECT_PROPERTIES_BULK
Parameters
The driver expects the following parameters.
| Parameter | VarType | Description |
| WPD_PROPERTY_OBJECT_PROPERTIES_BULK_OBJECT_FORMAT | VT_CLSID | Required. The format GUID that specifies what kind of objects to search for. |
| WPD_PROPERTY_OBJECT_PROPERTIES_BULK_PARENT_OBJECT_ID | VT_LPWSTR | Required. The object ID of the parent object where the search should begin. The parent is not included in the search. This can be the WPD_DEVICE_OBJECT_ID constant, which indicates that enumeration should begin from the device root. |
| WPD_PROPERTY_OBJECT_PROPERTIES_BULK_DEPTH | VT_UI4 | Required. The maximum depth to search, in levels, where 1 means immediate children only. If this number is greater than the actual depth, this is acceptable. To search to the maximum depth, specify 0xFFFFFFFF |
| WPD_PROPERTY_OBJECT_PROPERTIES_BULK_PROPERTY_KEYS | VT_UNKNOWN | Optional. An IPortableDeviceKeyCollection interface that contains the PROPERTYKEY values of the properties to retrieve. If this parameter is absent, all properties must be retrieved. |
Return Values
The driver should return the following results.
| Result | VarType | Description |
| WPD_PROPERTY_OBJECT_PROPERTIES_BULK_CONTEXT | VT_LPWSTR | Required. A unique ID that is used to identify this bulk property request in related calls. |
| WPD_PROPERTY_COMMON_HRESULT | VT_ERROR | Required. An HRESULT that indicates success or failure to carry out the command. If the caller is making an invalid request, the driver should return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED) and is not required to return any other result values. Error codes include Windows Portable Devices error codes or any other appropriate error codes. |
| WPD_PROPERTY_COMMON_DRIVER_ERROR_CODE | VT_UI4 | Optional. A driver-specific error code. This value is typically used by device vendors to improve diagnosis of device errors while using their applications. General purpose applications would ignore it and rely solely on WPD_PROPERTY_COMMON_HRESULT instead. |
Calling Methods
- IPortableDevicePropertiesBulk::QueueGetValuesByObjectFormat
Requirements
Header: Defined in PortableDevice.h
See Also