Miscellaneous Constants

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Miscellaneous String constants.

Constant/value Description
wiaIDUnknown
{00000000-0000-0000-0000-000000000000}
 Unknown ID. Default value for the FormatID parameter for the [Transfer](-wiaaut-iitem-transfer.md), [ShowTransfer](-wiaaut-icommondialog-showtransfer.md), and [ShowAcquireImage](-wiaaut-icommondialog-showacquireimage.md) methods. In this context, it implies any FormatID rather than an unknown FormatID, or you might think of it as unknown to the calling application. Any property that represents a GUID can also return this constant as an error result.
The following example shows how to determine if the file returned from [ShowAcquireImage](-wiaaut-icommondialog-showacquireimage.md) is in a known format.

Dim Img 'As ImageFile

Set Img = CommonDialog1.ShowAcquireImage
If Img.FormatID = wiaIDUnknown Then
MsgBox "Image format unknown"
End If
wiaAnyDeviceID
*

DeviceID for any Device. Default value for the DeviceID parameter for the [RegisterEvent](-wiaaut-idevicemanager-registerevent.md), [UnregisterEvent](-wiaaut-idevicemanager-unregisterevent.md), [RegisterPersistentEvent](-wiaaut-idevicemanager-registerpersistentevent.md), and [UnregisterPersistentEvent](-wiaaut-idevicemanager-unregisterpersistentevent.md) methods. This constant is defined here in case you want to explicitly use any device when calling these methods.

For example code, see [Download New Items as They are Created](-wiaaut-shared-samples.md) in Shared Samples.

Requirements
Minimum supported client
 Windows Vista [desktop apps only]
Minimum supported server
 Windows Server 2003 R2 [desktop apps only]
Header
Wiaaut.h
IDL
Wiaaut.idl