You can check the syntax of the email with such regular expression:
public static bool isEmail(string inputEmail)
{
inputEmail = NulltoString(inputEmail);
string strRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
@"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
@".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
Regex re = new Regex(strRegex);
if (re.IsMatch(inputEmail))
return (true);
else
return (false);
}
Or you can make SMTP check:
string[] host = (address.Split('@'));
string hostname = host[1];
IPHostEntry IPhst = Dns.Resolve(hostname);
IPEndPoint endPt = new IPEndPoint(IPhst.AddressList[0], 25);
Socket s= new Socket(endPt.AddressFamily,
SocketType.Stream,ProtocolType.Tcp);
s.Connect(endPt);
The following snippets are not mine, they are taken from this source:
http://stackoverflow.com/questions/3883518/can-i-check-if-an-email-address-exists-using-net[
^]