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LWia::GetPropertyGUID

Summary

Retrieves the GUID structure for any WIA property of type VT_CLSID (for example, WIA_IPA_FORMAT).

Syntax

#include "ltwrappr.h"

virtual L_INT LWia::GetPropertyGUID(pItem, pszID, uID, pGuidValue)

Parameters

L_VOID * pItem

Valid pointer to a type IWiaItem or IWiaItem2 object (IWiaItem if using WIA Version 1.0; IWiaItem2 if using WIA Version 2.0), which represents the item having the property.

Retrieve this parameter by either calling the LWia::GetRootItem function to get a pointer to the device's root item, or by enumerating the child items of the device through a call to LWia::EnumChildItems.

L_TCHAR * pszID

String pointer containing the equivalent property ID string for the WIA property ID (see example below):

Property ID	Property ID Equivalent String
WIA_IPA_TYM	WIA_IPA_TYMED_STR or "Media Type"
WIA_IPA_DEPTH	WIA_IPA_DEPTH_STR or "Bits Per Pixel"

If this parameter is NULL, then the WIA toolkit will use the ID passed through the uID parameter; otherwise, the pszID parameter will be used regardless of whether a valid property ID has been passed through the uID parameter.

L_UINT32 uID

The property ID for which you are obtaining the GUID structure.

The uID parameter is required only if the pszID parameter is NULL. If the pszID parameter is not NULL, pass 0 for uID.

GUID * pGuidValue

Pointer to a variable of type GUID to be updated with the retrieved property GUID value.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

This feature is available in LEADTOOLS version 16 or higher.

Call [LWia:GetPropertyGUID to retrieve the GUID structure for any WIA property of type VT_CLSID (for example, WIA_IPA_FORMAT).

Required DLLs and Libraries

LTWIA
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Example

class CMyWIA : public LWia 
{ 
public: 
   L_INT EnumItemsCB(L_INT nItemsCount, L_VOID * pItem); 
}; 
 
L_INT CMyWIA::EnumItemsCB(L_INT nItemsCount, L_VOID * pItem) 
{ 
   UNREFERENCED_PARAMETER(nItemsCount); 
 
   L_INT nRet; 
   GUID guidFormat; 
 
   if(pItem != NULL) 
   { 
      /* Get the current item's transfer format */ 
      nRet = GetPropertyGUID(pItem, NULL, WIA_IPA_FORMAT, &guidFormat); 
      if(nRet != WIA_SUCCESS) 
         return nRet; 
 
      /* You can also change the transfer format for that item. */ 
      guidFormat = WiaImgFmt_TIFF; 
      nRet = SetPropertyGUID(pItem, NULL, WIA_IPA_FORMAT, &guidFormat); 
      if(nRet != WIA_SUCCESS) 
         return nRet; 
 
      nRet = FreeItem(pItem); 
      if(nRet != WIA_SUCCESS) 
         return nRet; 
   } 
 
   return WIA_SUCCESS; 
} 
 
L_INT LWIA__GetPropertyGUIDExample() 
{ 
   L_INT nRet; 
   IWiaItem * pRootItem = NULL; 
   CMyWIA MyClass; 
 
   nRet = MyClass.SelectDeviceDlg(WiaDeviceTypeDefault, 0); 
   if(nRet != WIA_SUCCESS) 
      return nRet; 
 
   nRet = MyClass.GetRootItem(NULL, (L_VOID**)&pRootItem); 
   if(nRet != WIA_SUCCESS) 
      return nRet; 
 
   nRet = MyClass.EnumChildItems(pRootItem); 
   if(nRet != WIA_SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}