C# Definition:

    [StructLayout(LayoutKind.Sequential)]
    public struct DRIVE_LAYOUT_INFORMATION_EX
    {
        public PARTITION_STYLE 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:

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

    [FieldOffset(0)]
    public DRIVE_LAYOUT_INFORMATION_GPT Gpt;
}

Notes:

None.