using System.ComponentModel.DataAnnotations;

using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(test.IsValidEmail("Gerardo.ureña@suez.com"));

    }   

}

​

public static class test {

    private static readonly EmailAddressAttribute EmailValidator = new EmailAddressAttribute();

    public static bool IsValidEmail(this string email)

    {

        // You can also add validation against length if you want

        return !string.IsNullOrWhiteSpace(email) && EmailValidator.IsValid(email); 

    }

}