title: Retrieve all keys in a hash table into a string
body: <p>The coding language is C#3.0<br>
  What is the most optimum method to retrieve all hashtable keys into string separated by a delimiter ","<br>
  Is the for loop or the foreach loop the only option?  </p>
  
  <p>Update: the keys are already strings  </p>
  
  <p>Regards,<br>
  naveenj  </p>