IWiaItem2 interface
The IWiaItem2 interface provides applications with the same functionality as the IWiaItem interface (the ability to query devices to discover their capabilities, to access data transfer interfaces and item properties, and to control the device). It also provides application with the ability to dynamically create and use image processing filters that can come as extensions of the Windows Image Acquisition (WIA) 2.0 device drivers provided in Windows Vista.
Members
The IWiaItem2 interface inherits from the IUnknown interface. IWiaItem2 also has these types of members:
Methods
The IWiaItem2 interface has these methods.
| Method | Description |
|---|---|
| CheckExtension | Checks whether a specified extension is available on the machine and can be used by the IWiaItem2::GetExtension method. |
| CreateChildItem | Create a new child item. Adds IWiaItem2 objects to a device's IWiaItem2 tree. |
| DeleteItem | Removes the current IWiaItem2 object from the device's object tree. |
| DeviceCommand | Issues a command to a WIA 2.0 hardware device. |
| DeviceDlg | Displays a dialog box to the user to prepare for image acquisition. |
| Diagnostic | Not currently supported. |
| EnumChildItems | Creates an enumerator object and passes back a pointer to its IEnumWiaItem2 interface for folders with items in the IWiaItem2 tree of a WIA 2.0 device. |
| EnumDeviceCapabilities | Creates an enumerator that is used to ascertain the commands and events a WIA 2.0 device supports. |
| EnumRegisterEventInfo | The IWiaItem2::EnumRegisterEventInfo method creates an enumerator used to obtain information about events for which an application is registered. |
| FindItemByName | Searches an item's tree of subitems using the name as the search key. |
| GetExtension | Gets the extension interfaces that might come with a WIA 2.0 device driver. |
| GetItemCategory | Gets an item's category information. |
| GetItemType | Gets an item's type information. |
| GetParentItem | Gets the parent item in the tree that represents a WIA 2.0 hardware device. |
| GetPreviewComponent | Gets the WIA 2.0 preview component. |
| GetRootItem | Gets the root item of a tree of item objects used to represent a WIA 2.0 hardware device. |
Remarks
The WIA 2.0 item tree that an application can see is separate from the tree that is created and maintained by a WIA 2.0 minidriver. When a minidriver creates a tree of items, the WIA 2.0 Service uses this WIA 2.0 item tree as a guide to create identical copies that can be viewed by imaging applications. Items in the copied tree are called application items. Items in the tree created by a minidriver are called driver items. In Windows Vista the WIA 2.0 item trees are built of IWiaItem2 objects, each one of which implements the IWiaItem2 interface).
The IWiaItem2 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 Vista [desktop apps only] |
| Minimum supported server |
Windows Server 2008 [desktop apps only] |
| Header |
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| IDL |
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