IWMDMMetaData::QueryByIndex method (mswmdm.h)

The QueryByIndex method retrieves the value of a property specified by index.

Syntax

HRESULT QueryByIndex(
  [in]  UINT              iIndex,
  [out] WCHAR             **ppwszName,
  [out] WMDM_TAG_DATATYPE *pType,
  [out] BYTE              **ppValue,
  [out] UINT              *pcbLength
);

Parameters

[in] iIndex

Integer specifying the zero-based index of the property. The number of items is obtained through the GetItemCount call.

[out] ppwszName

Name of the property. Windows Media Device Manager allocates this memory, and the caller must free it using CoTaskMemFree.

[out] pType

An WMDM_TAG_DATATYPE enumerated value describing the type of data returned in ppValue.

[out] ppValue

Pointer to a pointer to a byte array that receives the content of the value if the method succeeds. This memory is allocated by Windows Media Device Manager, and the caller must free it using CoTaskMemFree.

[out] pcbLength

Pointer to the size, in bytes, of the byte array ppValue. If the value is a string, this includes the termination character.

Return value

The method returns an HRESULT. All the interface methods in Windows Media Device Manager can return any of the following classes of error codes:

• Standard COM error codes
• Windows error codes converted to HRESULT values
• Windows Media Device Manager error codes

For an extensive list of possible error codes, see Error Codes.

Requirements

Requirement	Value
Target Platform	Windows
Header	mswmdm.h
Library	Mssachlp.lib

See also

GetItemCount

IWMDMMetaData Interface

QueryByName

Setting Metadata on a File