References ▼
#include "ltwrappr.h"
virtual L_INT LTwain::QueryProperty (uCapability, ppltProperty, uStructSize)
Gets the available property values.
This is a capability constant defined by the TWAIN specification. For example, if the user wants the value for the transfer count, the uCapability will be ICAP_XFERCOUNT.
Pointer to a pointer to a LTWAINPROPERTYQUERY structure to be updated with the property values.
The structure will be internally allocated if the function is successful. The structure should be freed by calling the LTwain::FreePropQueryStructure function.
Size of the LTWAINPROPERTYQUERY structure, in bytes, for versioning. Use sizeof(LTWAINPROPERTYQUERY).
| Value | Meaning |
|---|---|
| SUCCESS | The function was successful. |
| < | An error occurred. Refer to Return Codes. |
Getting these values can help in determining which values a certain TWAIN source supports for a certain capability or property.
Required DLLs and Libraries
L_INT LTwain__QueryPropertyExample(L_INT16 uValue, CMyTwain *MyClass){L_INT nRet, nIndex;pLTWAINPROPERTYQUERY pltQuery = NULL;// Query capability possible valuesnRet = MyClass->QueryProperty (ICAP_XRESOLUTION, &pltQuery , sizeof(LTWAINPROPERTYQUERY));if (nRet != SUCCESS)return nRet;// Check for the available values of the file transfer propertyswitch (pltQuery->uType){case TWON_ONEVALUE:if (pltQuery->pltwOneValue->ItemType == TWTY_FIX32){pTW_FIX32 ptwFixVal = (pTW_FIX32)&(pltQuery->pltwOneValue->Item);if (ptwFixVal->Whole == uValue){nRet = MyClass->FreePropQueryStructure(&pltQuery);if(nRet != SUCCESS)return nRet;}}break;case TWON_ENUMERATION:if (pltQuery->pltwEnumeration->ItemType == TWTY_FIX32){pTW_FIX32 ptwFixVal;for (nIndex = 0; nIndex < (L_INT)pltQuery->pltwEnumeration->NumItems; nIndex ++){ptwFixVal = (pTW_FIX32)(pltQuery->pltwEnumeration->ItemList[nIndex]);if (ptwFixVal->Whole == uValue){nRet = MyClass->FreePropQueryStructure (&pltQuery);if(nRet != SUCCESS)return nRet;}}}break;}nRet = MyClass->FreePropQueryStructure (&pltQuery);return nRet;}