MSDN Library


This interface allows clients to obtain a string of bytes (an identity string) that uniquely identifies a particular accessible element

If server developers know the HWND of the object they want to annotate, they can use one of the following methods instead of using this method and getting an identity string.

HRESULT GetIdentityString (
  DWORD dwIDChild,
  BYTE** ppIDString,
  DWORD* pdwIDStringLen


[in] Specifies which child of the IAccessible object the caller wants to identify.
ppIDString, pdwIDStringLen
[out] Callee-allocated identity string and its length. Callee allocates this using CoTaskMemAlloc; caller must release using CoTaskMemFree when finished.

Return Values

Should always return S_OK, except under exceptional error conditions, such as low memory. If not supported, calling QueryInterface on IAccIdentity should fail.


The returned string should be considered opaque; clients should use it only as a whole, and should not attempt to dissect it or otherwise interpret it manually.

If a client knows or expects that a string is HWND--based, it can use IAccPropServices::DecomposeHwndIdentityString() to attempt to decompose the identity string.


  Windows NT/2000/XP/Server 2003: Included in Windows XP and Windows Server 2003.
  Windows 95/98/Me: Unsupported.
  Redistributable: Requires Active Accessibility 2.0 RDK on Windows NT 4.0 SP6 and Windows 98.
  Header: Declared in Oleacc.h; include Initguid.h before including Oleacc.h.

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