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IWiaDevMgr::SelectDeviceDlg method

The IWiaDevMgr::SelectDeviceDlg displays a dialog box that enables the user to select a hardware device for image acquisition.

Syntax


HRESULT SelectDeviceDlg(
  [in]           HWND hwndParent,
  [in]           LONG lDeviceType,
  [in]           LONG lFlags,
  [in, out]      BSTR *pbstrDeviceID,
  [out, retval]  IWiaItem **ppItemRoot
);

Parameters

hwndParent [in]

Type: HWND

Handle of the window that owns the Select Device dialog box.

lDeviceType [in]

Type: LONG

Specifies which type of WIA device to use. Can be set to StiDeviceTypeDefault, StiDeviceTypeScanner, or StiDeviceTypeDigitalCamera.

lFlags [in]

Type: LONG

Specifies dialog box behavior. Can be set to any of the following values:

ConstantMeaning
0Use the default behavior.
WIA_SELECT_DEVICE_NODEFAULTDisplay the dialog box even if there is only one matching device. For more information, see the Remarks section of this reference page.

 

pbstrDeviceID [in, out]

Type: BSTR*

On output, receives a string which contains the device's identifier string. On input, pass the address of a pointer if this information is needed, or NULL if it is not needed.

ppItemRoot [out, retval]

Type: IWiaItem**

Receives the address of a pointer to the IWiaItem interface of the root item of the tree that represents the selected WIA device. If no devices are found, it contains the value NULL.

Return value

Type: HRESULT

This method returns the following values:

Return ValueMeaning
S_OKA device was successfully selected.
S_FALSEThe user canceled the dialog box.
WIA_S_NO_DEVICE_AVAILABLEThere are no WIA hardware devices that match the specifications given in the lDeviceType parameter.

 

Remarks

This method creates and displays the Select Device dialog box so the user can select a WIA device for image acquisition. If a device is successfully selected, the IWiaDevMgr::SelectDeviceDlg method creates a hierarchical tree of IWiaItem objects for the device. It stores a pointer to the IWiaItem interface of the root item in the parameter ppItemRoot.

Particular types of devices may be displayed to the user by specifying the device types through the lDeviceType parameter. If only one device meets the specification, IWiaDevMgr::SelectDeviceDlg does not display the Select Device dialog box. Instead it creates the IWiaItem tree for the device and store a pointer to the IWiaItem interface of the root item in the parameter ppItemRoot. You can override this behavior and force IWiaDevMgr::SelectDeviceDlg to display the Select Device dialog box by passing WIA_SELECT_DEVICE_NODEFAULT as the value for the lFlags parameter.

If more than one WIA device matches the specification, all matching devices are displayed in the Select Device dialog box so the user may choose one.

Applications must call the IUnknown::Release method on the interface pointers they receive through the ppItemRoot parameter.

It is recommended that applications make device and image selection available through a menu item named From scanner or camera on the File menu.

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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