using System;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
string email = "an.email@ahost.com";
string regex = @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
Regex rgx = new Regex(regex);
Boolean result = rgx.IsMatch(email);
System.Console.WriteLine("{0} validation is {1}", email, result.ToString());
}
}
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