using System;
using System.Globalization;
using System.Text.RegularExpressions;
public bool IsValidEmail(string email)
{
if (string.IsNullOrWhiteSpace(email))
return false;
try
{
// Normalize the domain
email = Regex.Replace(email, @"(@)(.+)$", DomainMapper,
RegexOptions.None, TimeSpan.FromMilliseconds(200));
// Examines the domain part of the email and normalizes it.
string DomainMapper(Match match)
{
// Use IdnMapping class to convert Unicode domain names.
var idn = new IdnMapping();
// Pull out and process domain name (throws ArgumentException on invalid)
var domainName = idn.GetAscii(match.Groups[2].Value);
return match.Groups[1].Value + domainName;
}
}
catch (RegexMatchTimeoutException e)
{
return false;
}
catch (ArgumentException e)
{
return false;
}
try
{
return Regex.IsMatch(email,
@"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
@"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-0-9a-z]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$",
RegexOptions.IgnoreCase, TimeSpan.FromMilliseconds(250));
}
catch (RegexMatchTimeoutException)
{
return false;
}
}