StringBuilder去除最后一个字符 :sb.Remove(sb.Length-1, 1);
以“;”分隔某个字符串:
string[] stringlist=str.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
四舍五入 :Math.Round(total, 2, MidpointRounding.AwayFromZero);