注意：下面的代码原本不是我的想法。这只是Peter Bromberg代码article中的修改。
这段代码对我有用，但发送电子邮件有点慢（甚至只发一封），我不知道为什么。另外，我正在尝试发送HTML Body，但它总是发送TEXT Body。请帮忙。
提前谢谢你！
using System.Text;
using System.IO;
using System.Net.Sockets;
using System.Net;
using System.Net.Mail;
namespace SMTP
{
/// <summary>
/// provides methods to send email via smtp direct to mail server
/// </summary>
public static class SmtpDirect
{
public static System.Threading.ManualResetEvent GetHostEntryFinished =
new System.Threading.ManualResetEvent(false);
public class ResolveState
{
string hostName;
System.Net.IPHostEntry resolvedIPs;
public ResolveState(string host)
{
hostName = host;
}
public IPHostEntry IPs
{
get { return resolvedIPs; }
set { resolvedIPs = value; }
}
public string host
{
get { return hostName; }
set { hostName = value; }
}
}
/// <summary>
/// Get / Set the name of the SMTP mail server
/// </summary>
public static string SmtpServer { get; set; }
// Record the IPs in the state object for later use.
public static void GetHostEntryCallback(IAsyncResult ar)
{
ResolveState ioContext = (ResolveState)ar.AsyncState;
ioContext.IPs = Dns.EndGetHostEntry(ar);
GetHostEntryFinished.Set();
}
private enum SMTPResponse : int
{
CONNECT_SUCCESS = 220,
GENERIC_SUCCESS = 250,
DATA_SUCCESS = 354,
QUIT_SUCCESS = 221
}
/// <summary>
/// Send Email
/// </summary>
/// <param name="message"></param>
/// <returns></returns>
public static bool Send(MailMessage message)
{
try
{
GetHostEntryFinished.Reset();
ResolveState ioContext = new ResolveState(SmtpServer);
Dns.BeginGetHostEntry(ioContext.host,
new AsyncCallback(GetHostEntryCallback), ioContext);
// Wait here until the resolve completes (the callback
// calls .Set())
GetHostEntryFinished.WaitOne();
IPEndPoint endPt = new IPEndPoint(ioContext.IPs.AddressList[0], 25);
Socket s = new Socket(endPt.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
bool conn = false;
foreach (IPAddress ip in ioContext.IPs.AddressList)
{
endPt = new IPEndPoint(ioContext.IPs.AddressList[0], 25);
s = new Socket(endPt.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
s.Connect(endPt);
if (Check_Response(s, SMTPResponse.CONNECT_SUCCESS))
{
conn = true;
}
}
if (!conn)
{
s.Close();
return false;
}
Senddata(s, string.Format("HELO {0}\r\n", Dns.GetHostName()));
if (!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}
Senddata(s, string.Format("MAIL From: {0}\r\n", message.From));
if (!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}
string _To = message.To[0].ToString();
string[] Tos = _To.Split(new char[] { ';' });
foreach (string To in Tos)
{
Senddata(s, string.Format("RCPT TO: {0}\r\n", To));
if (!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}
}
if (message.CC != null)
{
Tos = message.CC.ToString().Split(new char[] { ';' });
foreach (string To in Tos)
{
Console.WriteLine("RCPT To");
Senddata(s, string.Format("RCPT TO: {0}\r\n", To));
if (!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}
}
}
StringBuilder Header = new StringBuilder();
Header.Append("From: " + message.From + "\r\n");
Tos = message.To.ToString().Split(new char[] { ';' });
Header.Append("To: ");
for (int i = 0; i < Tos.Length; i++)
{
Header.Append(i > 0 ? "," : "");
Header.Append(Tos[i]);
}
Header.Append("\r\n");
if (message.CC != null)
{
Tos = message.CC.ToString().Split(new char[] { ';' });
Header.Append("Cc: ");
for (int i = 0; i < Tos.Length; i++)
{
Header.Append(i > 0 ? "," : "");
Header.Append(Tos[i]);
}
Header.Append("\r\n");
}
Header.Append("Date: ");
Header.Append(DateTime.Now.ToString("ddd, d M y H:m:s z"));
Header.Append("\r\n");
Header.Append("Subject: " + message.Subject + "\r\n");
Header.Append("X-Mailer: SMTPDirect v1\r\n");
string MsgBody = message.Body;
if (!MsgBody.EndsWith("\r\n"))
MsgBody += "\r\n";
if (message.Attachments.Count > 0)
{
Header.Append("MIME-Version: 1.0\r\n");
Header.Append("Content-Type: multipart/mixed; boundary=unique-boundary-1\r\n");
Header.Append("\r\n");
Header.Append("This is a multi-part message in MIME format.\r\n");
StringBuilder sb = new StringBuilder();
sb.Append("--unique-boundary-1\r\n");
sb.Append("Content-Type: text/plain\r\n");
sb.Append("Content-Transfer-Encoding: 7Bit\r\n");
sb.Append("\r\n");
sb.Append(MsgBody + "\r\n");
sb.Append("\r\n");
foreach (object o in message.Attachments)
{
Attachment a = o as Attachment;
byte[] binaryData;
if (a != null)
{
FileInfo f = new FileInfo(a.Name);
sb.Append("--unique-boundary-1\r\n");
sb.Append("Content-Type: application/octet-stream; file=" + f.Name + "\r\n");
sb.Append("Content-Transfer-Encoding: base64\r\n");
sb.Append("Content-Disposition: attachment; filename=" + f.Name + "\r\n");
sb.Append("\r\n");
FileStream fs = f.OpenRead();
binaryData = new Byte[fs.Length];
long bytesRead = fs.Read(binaryData, 0, (int)fs.Length);
fs.Close();
string base64String = System.Convert.ToBase64String(binaryData, 0, binaryData.Length);
for (int i = 0; i < base64String.Length;)
{
int nextchunk = 100;
if (base64String.Length - (i + nextchunk) < 0)
nextchunk = base64String.Length - i;
sb.Append(base64String.Substring(i, nextchunk));
sb.Append("\r\n");
i += nextchunk;
}
sb.Append("\r\n");
}
}
MsgBody = sb.ToString();
}
Senddata(s, ("DATA\r\n"));
if (!Check_Response(s, SMTPResponse.DATA_SUCCESS))
{
s.Close();
return false;
}
Header.Append("\r\n");
Header.Append(MsgBody);
Header.Append(".\r\n");
Header.Append("\r\n");
Header.Append("\r\n");
Senddata(s, Header.ToString());
if (!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
{
s.Close();
return false;
}
Senddata(s, "QUIT\r\n");
Check_Response(s, SMTPResponse.QUIT_SUCCESS);
s.Close();
return true;
}
catch (Exception ex)
{
return false;
}
}
private static void Senddata(Socket s, string msg)
{
try
{
byte[] _msg = Encoding.ASCII.GetBytes(msg);
s.Send(_msg, 0, _msg.Length, SocketFlags.None);
}
catch (Exception ex)
{
Console.WriteLine("SendData Error: " + ex.Message);
}
}
private static bool Check_Response(Socket s, SMTPResponse response_expected)
{
string sResponse;
int response;
byte[] bytes = new byte[1024];
while (s.Available == 0)
{
System.Threading.Thread.Sleep(100);
}
s.Receive(bytes, 0, s.Available, SocketFlags.None);
sResponse = Encoding.ASCII.GetString(bytes);
response = Convert.ToInt32(sResponse.Substring(0, 3));
if (response != (int)response_expected)
return false;
return true;
}
}
}
要测试上面的代码我使用这个
SMTP.SmtpDirect.SmtpServer = "myhost.loc";
MailMessage msg = new MailMessage();
msg.Body = "TEST";
msg.From = new MailAddress("from@mail.com");
msg.To.Add("to@mail.com");
msg.Subject = "TEST SUBJECT";
//msg.Headers.Add("Reply-to", "");
if (SMTP.SmtpDirect.Send(msg))
{
Console.WriteLine("Sent OK");
}
else
{
Console.WriteLine("Something BAD Happened!");
}
答案 0 :(得分：1)
您可以同时发送多个电子邮件。但要小心并发邮件发送操作的数量。通过多次测试调整并发邮件发送操作的数量。这种方法可以帮到你
答案 1 :(得分：0)
从邮件发送html正文。使用
msg.BodyFormat = MailFormat.Html;
如果您在当前类中使用System.Web.Mail命名空间。（请不要使用此命名空间，因为MailFormat在更高.net框架中已过时）
否则使用
msg.IsBodyHtml = true;
如果您使用的是System.Net.Mail命名空间。
如果无效，请尝试添加此代码段。：
AlternateView htmlView =
AlternateView.CreateAlternateViewFromString(yourbody, Encoding.UTF8, "text/html");
msg.AlternateViews.Add(htmlView);
msg.Body = yourbody;
msg.IsBodyHtml = true;