C# Definition:

[ComImport]
[Guid("00000139-0000-0000-c000-000000000046")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IEnumSTATPROPSTG
{
    int Next(
        uint count,
        [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 0), Out]
        STATPROPSTG[] elements,
        out uint pceltFetched);

    void Skip(uint count);

    void Reset();

    [return: MarshalAs(UnmanagedType.Interface)]
    IEnumSTATPROPSTG Clone();
}

User-Defined Types:

[StructLayout(LayoutKind.Sequential)]
internal struct STATPROPSTG
{
    [MarshalAs(UnmanagedType.LPWStr)]
    public string lpwstrName;
    public uint propid;
    public ushort vt;

}