C# Definition:

[ComImport, Guid ( "8BE2D872-86AA-4d47-B776-32CCA40C7018" ), InterfaceType ( ComInterfaceType.InterfaceIsIUnknown )]
interface IKnownFolderManager
[ComImport, Guid ( "38521333-6A87-46A7-AE10-0F16706816C3" ), InterfaceType ( ComInterfaceType.InterfaceIsIUnknown )]
interface IKnownFolder
{
    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void FolderIdFromCsidl ( [In] int nCsidl, out Guid pfid );
    void GetId ( out Guid pkfid );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void FolderIdToCsidl ( [In] ref Guid rfid, out int pnCsidl );
    // Not yet supported - adding to fill slot in vtable
    void spacer1 ( );
    //[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
    //void GetCategory(out mbtagKF_CATEGORY pCategory);

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void GetFolderIds ( [Out] IntPtr ppKFId, [In, Out] ref uint pCount );
    void GetShellItem ( [In] uint dwFlags, ref Guid riid, out IShellItem ppv );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void GetFolder ( [In] ref Guid rfid, [MarshalAs ( UnmanagedType.Interface )] out IKnownFolder ppkf );
    void GetPath ( [In] uint dwFlags, [MarshalAs ( UnmanagedType.LPWStr )] out string ppszPath );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void GetFolderByName ( [In, MarshalAs ( UnmanagedType.LPWStr )] string pszCanonicalName,
                   [MarshalAs ( UnmanagedType.Interface )] out IKnownFolder ppkf );
    void SetPath ( [In] uint dwFlags, [In, MarshalAs ( UnmanagedType.LPWStr )] string pszPath );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void RegisterFolder ( [In] ref Guid rfid, [In] ref NativeMethods.KNOWNFOLDER_DEFINITION pKFD );
    void GetLocation ( [In] uint dwFlags, [Out, ComAliasName ( "ShellObjects.wirePIDL" )] IntPtr ppidl );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void UnregisterFolder ( [In] ref Guid rfid );
    void GetFolderType ( out Guid pftid );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void FindFolderFromPath ( [In, MarshalAs ( UnmanagedType.LPWStr )] string pszPath,
                  [In] NativeMethods.FFFP_MODE mode,
                  [MarshalAs ( UnmanagedType.Interface )] out IKnownFolder ppkf );
    void GetRedirectionCapabilities ( out uint pCapabilities );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void FindFolderFromIDList ( [In] IntPtr pidl, [MarshalAs ( UnmanagedType.Interface )] out IKnownFolder ppkf );

    [MethodImpl ( MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime )]
    void Redirect ( [In] ref Guid rfid, [In] IntPtr hwnd, [In] uint Flags,
            [In, MarshalAs ( UnmanagedType.LPWStr )] string pszTargetPath, [In] uint cFolders,
            [In] ref Guid pExclusion, [MarshalAs ( UnmanagedType.LPWStr )] out string ppszError );
    // Not yet supported - adding to fill slot in vtable
    void spacer2 ( );
    //[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
    //void GetFolderDefinition(out tagKNOWNFOLDER_DEFINITION pKFD);
}

VB Definition:

<ComImport> _
<Guid("TODO")> _
'TODO: Insert <InterfaceType(ComInterfaceType.InterfaceIsIUnknown)> _ if this doesn't derive from IDispatch
Interface IKnownFolderManager
Interface IKnownFolder
TODO
End Interface