title: Creating a comma separated list from IList<string> or IEnumerable<string>
body: <p>What is the cleanest way to create a comma-separated list of string values from an <code>IList&lt;string&gt;</code> or <code>IEnumerable&lt;string&gt;</code>?</p>
  
  <p><code>String.Join(...)</code> operates on a <code>string[]</code> so can be cumbersome to work with when types such as <code>IList&lt;string&gt;</code> or <code>IEnumerable&lt;string&gt;</code> cannot easily be converted into a string array.</p>