1. 从System.String[]转到List<System.String>
System.String[] str={"str","string","abc"};
List<System.String> listS=new List<System.String>(str);

2. 从List<System.String>转到System.String[]
List<System.String> listS=new List<System.String>();
listS.Add("str");
listS.Add("hello");
System.String[] str=listS.ToArray();