验证输入的正确性

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);
}

验证邮件地址的正确性：

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);

//Attempting to connect
if(!Check_Response(s, SMTPResponse.CONNECT_SUCCESS))
{
s.Close();
return false;
}

//HELO server
Senddata(s, string.Format("HELO {0}\r\n", Dns.GetHostName() ));
if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}

//Identify yourself
//Servers may resolve your domain and check whether you are listed in BlackLists etc.
Senddata(s, string.Format("MAIL From: {0}\r\n","testexample@deepak.portland.co.uk"));
if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{

s.Close();
return false;
}


//Attempt Delivery (I can use VRFY, but most SMTP servers only disable it for security reasons)
Senddata(s, address);
if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{

s.Close();
return false;
}
return (true);