How to get comma seprated string from List Item

Suppose i want to get the output as comma seprated string from my list here is the code of it.

 private string GetStringFromListItem()
        {
            List<string> alist = new List<string>();
            alist.Add("One");
            alist.Add("Two");
            alist.Add("Three");

            var rtnVal = from x in alist select x;

            return string.Join(",", rtnVal.ToArray());
        }

You can use this code for LinqToSql also. Very handy code for data conversion and migration projects.