using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Model { internal class CommonLib { public static string RemoveUpToSecondDot(string s) { if (string.IsNullOrEmpty(s)) return s; int first = s.IndexOf('.'); if (first < 0) return s; int second = s.IndexOf('.', first + 1); if (second < 0) return s; // 或 return string.Empty,根据需求 return s.Substring(second + 1); } } }