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.

MethodDescription
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 MethodsDescription
IUnknown::QueryInterface Returns pointers to supported interfaces.
IUnknown::AddRef Increments reference count.
IUnknown::Release Decrements reference count.

 

Requirements

Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]

Header

Wia.h

IDL

Wia.idl

 

 

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