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

See also

IWiaMiniDrv::drvValidateItemProperties

wiasGetChangedValueFloat

wiasGetChangedValueGuid

wiasGetChangedValueLong

wiasGetChangedValueStr