C# Definition:

    [StructLayout(LayoutKind.Sequential)]
    public struct DRIVE_LAYOUT_INFORMATION_EX
    {
        public PartitionStyle PartitionStyle;

        public int PartitionCount;

        public DRIVE_LAYOUT_INFORMATION_UNION DriveLayoutInformaiton;

        [MarshalAs(UnmanagedType.ByValArray, ArraySubType = UnmanagedType.Struct, SizeConst = 0x16)]
        public PARTITION_INFORMATION_EX[] PartitionEntry;
    }

VB Definition:

Structure DRIVE_LAYOUT_INFORMATION_EX
   Public TODO
End Structure

User-Defined Field Types:

    public enum PartitionStyle : int
    {
        MasterBootRecord = 0,
        GuidPartitionTable = 1,
        Raw = 2
    }

    [StructLayout(LayoutKind.Explicit)]
    public struct DRIVE_LAYOUT_INFORMATION_UNION
    {
        [FieldOffset(0)]
        public DRIVE_INFORMATION_LAYOUT_MBR Mbr;

        [FieldOffset(0)]
        public DRIVE_INFORMATION_LAYOUT_GPT Gpt;
    }

Notes:

None.