Unions in C#?

Hi,
I've got in an old C++ program a struct in which a integer was stored. The integer was some encoded way for storing a time value. For that the struct was build up as a union:

Code:

---

struct MYSTRUCT
{
  public:
    union
      {
      DWORD dwDts;
      struct _datetime
        {
        BYTE byMinute,
            byHour,
            byDay,
            byMonth;
        } dt;     
      };

---

Now I have to make the same functionality availible for C# but there's nothing like a union in C#. How could I do that in C#?

thanks in Advance

Akademos