how to implement typedef struct union in C#

Hi guys,

I have to rewrite this C++ code in C#. C# does not support typedef or union. How can I do this in C# ?

typedef enum {
TYPE_FLOAT, TYPE_STRING,TYPE_INTEGER, TYPE_DATETIME
} tdFuncType;

typedef struct {
   char           szNm[256];          // Identifier name, if not constant or computed
   tdFuncType ft;
   union {
       double         dFloat;           // TYPE_FLOAT
       long           lInteger;           // TYPE_INTEGER
       time_t         tDateTime;      // TYPE_DATETIME
       char           szString[256];  // TYPE_STRING, max string size is 255
       } val;
   } tdFuncValue;

// All values
typedef struct {
   long            lCt;     // Number of actual values: 1 to 11
   tdFuncValue fv[11]; // Values
   } tdFuncValues;

Any ideas ?

Thanks.

Pr.