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IAccPropServer::GetPropValue method (oleacc.h)

  • Artykuł

Retrieves a property value for an accessible element.

Syntax

HRESULT GetPropValue(
  [in]  const BYTE *pIDString,
  [in]  DWORD      dwIDStringLen,
  [in]  MSAAPROPID idProp,
  [out] VARIANT    *pvarValue,
  [out] BOOL       *pfHasProp
);

Parameters

[in] pIDString

Type: const BYTE*

Contains a string that identifies the property being requested.

[in] dwIDStringLen

Type: DWORD

Specifies the length of the identity string specified by the pIDString parameter.

[in] idProp

Type: MSAAPROPID

Specifies a GUID indicating the desired property.

[out] pvarValue

Type: VARIANT*

Specifies the value of the overridden property. This parameter is valid only if pfHasProp is TRUE. The server must set this to VT_EMPTY if pfHasProp is set to FALSE.

[out] pfHasProp

Type: BOOL*

Indicates whether the server is supplying a value for the requested property. The server should set this to TRUE if it is returning an overriding property or to FALSE if it is not returning a property (in which case it should also set pvarValue to VT_EMPTY).

Return value

Type: HRESULT

Return S_OK, except under exceptional error conditions such as low memory. If the specified property is not overridden, then pfHasProp should be set to FALSE and pvarValue should be set to VT_EMPTY by the server.

Remarks

If a single callback object is registered for annotating multiple accessible elements, the identity string can be used to determine which element this request refers to.

If the accessible element is HWND-based, IAccPropServices::DecomposeHwndIdentityString can be used to extract the HWND/idObject/idChild from the identity string.

If the callback has a value to return for the specified property, it should return it in pvarValue and set pfHasProp to TRUE. Otherwise it should set pvarValue to VT_EMPTY and set pfHasProp to FALSE. In this latter case, the original IAccessible interface pointer will be used to obtain a value for this property.

Requirements

Requirement Value
Minimum supported client Windows Vista or Windows XP
Minimum supported server Windows Server 2003
Target Platform Windows
Header oleacc.h (include OleAcc.h Include Initguid.h first.)
DLL Oleacc.dll
Redistributable Active Accessibility 2.0 RDK on Windows NT 4.0 with SP6 and later and Windows 98