IWMDMOperation::GetObjectAttributes method (mswmdm.h)

Article
02/22/2024

The GetObjectAttributes method allows the application to specify attributes for an object being written to a device. Windows Media Device Manager calls this method before a file is written to the device in order to learn the file's attributes.

Syntax

HRESULT GetObjectAttributes(
  [out] DWORD         *pdwAttributes,
  [out] _WAVEFORMATEX *pFormat
);

Parameters

[out] pdwAttributes

Pointer to a DWORD that specifies the attributes defined in the IWMDMStorage::GetAttributes method.

[out] pFormat

Pointer to a _WAVEFORMATEX structure that specifies the audio format for files with audio data attributes.

Return value

The application should return one of the following HRESULT values.

Return code	Description
S_OK	The read operation should continue.
WMDM_E_USER_CANCELLED	The read operation should be cancelled without finishing.
E_FAIL	An unspecified error occurred, and the read operation should be cancelled without finishing.

Remarks

When transferring data to the device, you should provide object attributes for optimal transference.

Examples

The following C++ code implements the GetObjectAttributes method. It tries to determine if the file being read (m_File) is a file or folder, and set the returned attributes accordingly.


HRESULT GetObjectAttributes(DWORD* pdwAttributes, _WAVEFORMATEX* pFormat)
{
    // TODO: Display the message: IWMDMOperation event--GetObjectAttributes.
    *pdwAttributes = WMDM_FILE_ATTR_FILE | 
        WMDM_STORAGE_ATTR_REMOVABLE | 
        WMDM_FILE_ATTR_AUDIO;

    BY_HANDLE_FILE_INFORMATION fileInformation;
    if (GetFileInformationByHandle(m_File, &fileInformation))
    {
        if (fileInformation.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
            *pdwAttributes |= WMDM_FILE_ATTR_FOLDER;
        else
            *pdwAttributes |= WMDM_FILE_ATTR_FILE;

        if (fileInformation.dwFileAttributes & FILE_ATTRIBUTE_READONLY)
            *pdwAttributes |= FILE_ATTRIBUTE_READONLY;
    }

    return S_OK;
}

Requirements

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

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