WIA_PROPERTY_CONTEXT

WIA_PROPERTY_CONTEXT structure

The WIA_PROPERTY_CONTEXT structure stores property identifiers and their context.

Syntax


typedef struct _WIA_PROPERTY_CONTEXT {
  ULONG  cProps;
  PROPID *pProps;
  BOOL   *pChanged;
} WIA_PROPERTY_CONTEXT, *PWIA_PROPERTY_CONTEXT;

Members

cProps

Specifies the number of property identifiers stored in this structure.

pProps

Is an array of property identifiers that indicate the properties being written.

pChanged

Is an array of Boolean values indicating which properties are changing. A member of this array is TRUE if the corresponding property is changing, and FALSE if the corresponding property is not changing. That is, if pChanged[n] is TRUE, pProps[n] will be changed, and if pChanged[n] is FALSE, pProps[n] will not be changed.

Remarks

The Boolean values indicate whether the corresponding property is being written (changed) by an application calling IPropertyStorage::WriteMultiple, which is described in the Microsoft Windows SDK documentation.

Several WIA service library functions use the WIA_PROPERTY_CONTEXT structure. The wiasCreatePropContext and wiasFreePropContext functions use it when a property context is created or freed. The wiasIsPropChanged and wiasSetPropChanged use this structure to determine whether a property changed, and to modify a property context when the property does change. The wiasGetChangedValueXxx functions use this structure to determine whether a property of a certain type has changed. The wiasUpdateValidFormat and wiasUpdateScanRect use it to, respectively, update a property context and to update the scanning area sizes for a scanning device.

Requirements

Version

Available in Windows Me and in Windows XP and later versions of the Windows operating systems.

Header

Wiamindr_lh.h (include Wiamindr.h)

See also

wiasCreatePropContext
wiasFreePropContext
wiasIsPropChanged
wiasSetPropChanged
wiasGetChangedValueFloat
wiasGetChangedValueGuid
wiasGetChangedValueLong
wiasGetChangedValueStr
wiasUpdateValidFormat
wiasUpdateScanRect

 

 

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