using System; using System.Data; using System.Text.RegularExpressions; class Class1{ static void Main(string[] args){ string IsNotNum = "111west"; string IsNum = " +111 "; string IsFloat = " 23.11 "; string IsExp = " +23 e+11 "; Console.WriteLine(IsUnsignedIntegerRegEx(IsNum)); // True Console.WriteLine(IsUnsignedIntegerRegEx(IsNotNum)); // False Console.WriteLine(IsUnsignedIntegerRegEx(IsFloat)); // False Console.WriteLine(IsUnsignedIntegerRegEx(IsExp)); // False } public static bool IsUnsignedIntegerRegEx(string str) { str = str.Trim(); return (Regex.IsMatch(str, @"^+?d+$")); } }