IWiaItem interface

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.

Note  For Windows Vista applications, use IWiaItem2 instead of IWiaItem.

Members

The IWiaItem interface inherits from the IUnknown interface. IWiaItem also has these types of members:

Methods

The IWiaItem interface has these methods.

MethodDescription
AnalyzeItem

The IWiaItem::AnalyzeItem method causes the WIA hardware device to acquire and try to detect what data types are present.

CreateChildItem

The IWiaItem::CreateChildItem method is used by applications to add IWiaItem objects to the IWiaItem tree of a device.

DeleteItem

The IWiaItem::DeleteItem method removes the current IWiaItem object from the object tree of the device.

DeviceCommand

The IWiaItem::DeviceCommand issues a command to a WIA hardware device.

DeviceDlg

The IWiaItem::DeviceDlg method is used by applications to display a dialog box to the user to prepare for image acquisition.

Diagnostic

Not currently supported.

DumpDrvItemData

Not currently supported.

DumpItemData

Not currently supported.

DumpTreeItemData

Not currently supported.

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 WIA device.

EnumDeviceCapabilities

The IWiaItem::EnumDeviceCapabilities method creates an enumerator that is used to ascertain the commands and events a WIA device supports.

EnumRegisterEventInfo

The IWiaItem::EnumRegisterEventInfo method creates an enumerator used to obtain information about events for which an application is registered.

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.

GetItemType

The IWiaItem::GetItemType method is called by applications to obtain the type information of an item.

GetRootItem

The IWiaItem::GetRootItem method retrieves the root item of a tree of item objects used to represent a 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:

Valid On Root Item Only IWiaItem::DeviceCommand
  IWiaItem::DeviceDlg
  IWiaItem::EnumDeviceCapabilities
  IWiaItem::EnumRegisterEventInfo
Valid On All Items IWiaItem::AnalyzeItem
  IWiaItem::CreateChildItem
  IWiaItem::DeleteItem
  IWiaItem::EnumChildItems
  IWiaItem::FindItemByName
  IWiaItem::GetItemType
  IWiaItem::GetRootItem

 

The IWiaItem 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 2000 Professional, Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

Wia.h

Library

Wiaguid.lib

DLL

Wiaservc.dll

 

 

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