1、ArrarList 转换为 string[] : ArrayList list = new ArrayList(); list.Add("aaa"); list.Add("bbb"); //转换成数组 string[] arrString = (string[])list.ToArray(typeof( string)) ; 2、string[] 转换为 ArrarList : ArrayList list = new ArrayList(new string[] { "aaa", "bbb" }); 3、ArrayList 转换为 string : ArrayList list = new ArrayList(); list.Add("aaa"); list.Add("bbb"); //转换成数组 string str= string.Join(",", (string[])list.ToArray(typeof( string))); 4、string 转换为 ArrayList : string str="1,2,3,4,5"; ArrayList b = new ArrayList( str.Split(',') ) ;