title: Convert a string as a MAC Address
body: <p>Convert a string into mac address as example <code>0000001</code> need to change as <code>00:00:01</code> In php i can get it by this <code>$HexVal=rtrim(strtoupper(chunk_split($hexval, 2, ':')),':');</code> i need exactly same in C#.
  I have the first 6 value as 00:01:AB and i got the last six value from a decimal number. If i input 1 then it needs to change as 00:00:01. so then i con-cat to get my full mac as 00:00:AB:00:00:01.</p>