1.List<string> 转数组,字符串
string[] strs= list.ToArray();string s = string.Join(",", list.ToArray());//数组转list
string[] strArr = new string[3] { "1", "2", "3" };
List<string> strList = strArr.ToList();
2.字符串是否数字
if (int.TryParse(i, out a) == false)int num = Convert.ToInt32(str)