List<> convert to string[]
List<string> list=new List<string>(); string str=list.ToArray();
String[] convert to List<>
string[] str={"str1","str2","str3"}; List<string> list=new List<string>(str);
List<> convert to String
List<string> list=new List<string>(); string str=String.Join(";",list.ToArray());