IWiaItem interface (wia_xp.h)
Each Windows Image Acquisition (WIA) hardware device is represented to an application as a hierarchical tree of IWiaItem objects. The IWiaItem interface provides applications with the ability to query devices to discover their capabilities. It also provides access to data transfer interfaces and item properties. In addition, the IWiaItem interface provides methods to enable applications to control the device.
Inheritance
The IWiaItem interface inherits from the IUnknown interface. IWiaItem also has these types of members:
Methods
The IWiaItem interface has these methods.
| IWiaItem::AnalyzeItem The IWiaItem::AnalyzeItem method causes the Windows Image Acquisition (WIA) hardware device to acquire and try to detect what data types are present. |
| IWiaItem::CreateChildItem The IWiaItem::CreateChildItem method is used by applications to add IWiaItem objects to the IWiaItem tree of a device. |
| IWiaItem::DeleteItem The IWiaItem::DeleteItem method removes the current IWiaItem object from the object tree of the device. |
| IWiaItem::DeviceCommand The IWiaItem::DeviceCommand issues a command to a Windows Image Acquisition (WIA) hardware device. |
| IWiaItem::DeviceDlg The IWiaItem::DeviceDlg method is used by applications to display a dialog box to the user to prepare for image acquisition. |
| IWiaItem::Diagnostic This method is not supported. (IWiaItem.Diagnostic) |
| IWiaItem::DumpDrvItemData This method is not supported. (IWiaItem.DumpDrvItemData) |
| IWiaItem::DumpItemData This method is not supported. (IWiaItem.DumpItemData) |
| IWiaItem::DumpTreeItemData This method is not supported. (IWiaItem.DumpTreeItemData) |
| IWiaItem::EnumChildItems The IWiaItem::EnumChildItems method creates an enumerator object and passes back a pointer to its IEnumWiaItem interface for non-empty folders in a IWiaItem tree of a Windows Image Acquisition (WIA) device. |
| IWiaItem::EnumDeviceCapabilities The IWiaItem::EnumDeviceCapabilities method creates an enumerator that is used to ascertain the commands and events a Windows Image Acquisition (WIA) device supports. |
| IWiaItem::EnumRegisterEventInfo The IWiaItem::EnumRegisterEventInfo method creates an enumerator used to obtain information about events for which an application is registered. |
| IWiaItem::FindItemByName The IWiaItem::FindItemByName method searches an item's tree of sub-items using the name as the search key. Each IWiaItem object has a name as one of its standard properties. |
| IWiaItem::GetItemType The IWiaItem::GetItemType method is called by applications to obtain the type information of an item. |
| IWiaItem::GetRootItem The IWiaItem::GetRootItem method retrieves the root item of a tree of item objects used to represent a Windows Image Acquisition (WIA) hardware device. |
Remarks
Some of the methods of the IWiaItem interface are valid only on the root item of the device's tree. Other methods are valid on all items. The methods are grouped as follows:
The IWiaItem interface, like all Component Object Model (COM) interfaces, inherits the IUnknown interface methods.
| IUnknown Methods | Description |
|---|---|
| IUnknown::QueryInterface | Returns pointers to supported interfaces. |
| IUnknown::AddRef | Increments reference count. |
| IUnknown::Release | Decrements reference count. |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional, Windows XP [desktop apps only] |
| Minimum supported server | Windows Server 2003 [desktop apps only] |
| Target Platform | Windows |
| Header | wia_xp.h (include Wia.h) |