WIAS_CHANGED_VALUE_INFO structure (wiamindr_lh.h)
The WIAS_CHANGED_VALUE_INFO structure is used to store the current and previous values of a property.
Syntax
typedef struct _WIAS_CHANGED_VALUE_INFO {
BOOL bChanged;
LONG vt;
union {
LONG lVal;
FLOAT fltVal;
BSTR bstrVal;
GUID guidVal;
} Old;
union {
LONG lVal;
FLOAT fltVal;
BSTR bstrVal;
GUID guidVal;
} Current;
} WIAS_CHANGED_VALUE_INFO, *PWIAS_CHANGED_VALUE_INFO;
Members
bChanged
Is a Boolean that indicates whether a property has changed. That is, if the property's current value is different from its value before IWiaMiniDrv::drvValidateItemProperties was called. Upon return from one of the wiasGetChangedValueXxx functions, this member is TRUE if the property changed, and FALSE if the property did not change.
vt
Specifies the variant data type for the property. This member can be one of the following:
VT_UI1
VT_UI2
VT_UI4
VT_I2
VT_I4
VT_R4
VT_R8
VT_CLSID
VT_BSTR
See the PROPVARIANT structure for more information.
Old
Old.lVal
Old.fltVal
Old.bstrVal
Old.guidVal
Current
Current.lVal
Current.fltVal
Current.bstrVal
Current.guidVal
Remarks
The wiasGetChangedValueXxx functions, use this structure to determine whether a property of a certain type has been changed by an application. These functions are used when the minidriver performs property validation, which occurs within the body of IWiaMiniDrv::drvValidateItemProperties.
Requirements
| Requirement | Value |
|---|---|
| Header | wiamindr_lh.h (include Wiamindr.h) |