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IWiaItem2 interface

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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
Wia.h
IDL
Wia.idl