how to Convert string MAC Address to Hex [closed]

Answer 1

The MAC address is very nearly a hex string. In fact, if you remove the ':' characters, you have a hex string.

 string hex = macAddress.Replace(":", "");

To the original question

00:18:4d:D0:9d:62

would simply be

00184dD09d62

and not the same as (or as long as)

466F7572746820466C6F6F72

My original reading of the question (which is probably incorrect) was that the OP wanted the base 10 equivalent of the hex number. If any other representation is desired, one can remove the colons with string.Replace and then parse the number using Convert.ToUInt64

string hex = macAddress.Replace(":", "");
uint64 macAsNumber = Convert.ToUInt64(hex, 16);

The number can then be converted to a string in whatever format is desired.