Validate Email

public static class Extensions
{
    public static bool        IsValidEmailAddress(this string s)
    {
        Regex regex = new          Regex(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");
        return regex.IsMatch(s);
    }
}

string customerEmailAddress = "test@test.com";
customerEmailAddress.IsValidEmailAddress()