C#基于SMTP协议发送电子邮件

1、C#基于SMTP协议发送电子邮件本代码示例演示了使用TcpClient和NetWorkStream基于SMTP协议发送电子邮件的全部过程，代码在VS2010中可以直接运行调用方式如下：ClsSendMail obj = new ClsSendMail();obj.UserName = "你的邮箱"obj.PassWord = "邮箱密码"bool flag = obj.Send("smtp地址", "你的邮箱", "发送人姓名", "收件人", "抄送人"

2、,true, "主题", "邮件内容");public class ClsSendMail #region 构造函数 public ClsSendMail() _listMailTo = new List<string>(); _listMailccTo = new List<string>(); _listAttachments = new List<string>(); InitSmtpCode(); public ClsSendMail(string strSmtpServer, int intPort, str

3、ing strUserName, string strPassword) this._strSmtpServer = strSmtpServer; this._intPort = intPort; this._strUserName = strUserName; this._strPassWord = strPassword; _listMailTo = new List<string>(); _listMailccTo = new List<string>(); _listAttachments = new List<string>(); InitSmtp

4、Code(); #endregion #region 成员变量 private string _strSmtpServer = "" /邮件服务器地址 private int _intPort = 25; /服务器端口 private string _strUserName = "" / SMTP认证时使用的用户名 private string _strPassWord = "" / SMTP认证时使用的密码 private string _strMailFrom = "" / 发件人地址 private stri

5、ng _strMailFromName = "" / 发件人姓名 private List<string> _listMailTo; / 收件人列表 private List<string> _listMailccTo; / 抄送收件人列表 private bool _IsHtml = false; / 是否Html邮件 private string _strPriority = "Normal" / 邮件发送优先级 private string _strSubject = "" / 邮件主题 private

6、string _strBody = "" / 邮件正文 private List<string> _listAttachments; / 邮件附件列表 private string _strCharSet = "GB2312" / 设定语言代码，默认设定为GB2312 private TcpClient client; / TcpClient对象，用于连接服务器 private NetworkStream NetStream; / NetworkStream对象 private Hashtable hsErrCode = new Hashta

7、ble(); / SMTP错误代码哈希表 private Hashtable hsRigCode = new Hashtable(); / SMTP正确代码哈希表 private string CRLF = "rn" /回车符号 private string ErrMsg = "" /记录错误消息 #region MailPriority / <summary> / 邮件发送优先级(可设置为"High","Normal","Low"或"1","3&quo

8、t;,"5") / </summary> public enum MailPriority High, Normal, Low #endregion #region SmtpServer / <summary> / 邮件服务器地址 / </summary> public string SmtpServer get return this._strSmtpServer; set this._strSmtpServer = value; #endregion #region Port / <summary> / 服务器端口 / &

9、lt;/summary> public int Port get return this._intPort; set this._intPort = value; #endregion #region UserName / <summary> / SMTP认证时使用的用户名 / </summary> public string UserName get return this._strUserName; set this._strUserName = value; #endregion #region PassWord / <summary> / SM

10、TP认证时使用的密码 / </summary> public string PassWord get return this._strPassWord; set this._strPassWord = value; #endregion #region Priority / <summary> / 优先级 / </summary> public string Priority get return this._strPriority; set this._strPriority = value; #endregion #region CharSet / &l

11、t;summary> / 设定语言代码，默认设定为GB2312 / </summary> public string CharSet get return this._strCharSet; set this._strCharSet = value; #endregion #endregion #region 成员函数 #region InitSmtpCode 初始化SMTP服务器返回结果Hash表 / <summary> / 初始化SMTP服务器返回结果Hash表 / </summary> private void InitSmtpCode() hs

12、ErrCode.Add("500", "邮箱地址错误"); hsErrCode.Add("501", "参数格式错误"); hsErrCode.Add("502", "命令不可实现"); hsErrCode.Add("503", "服务器需要SMTP验证"); hsErrCode.Add("504", "命令参数不可实现"); hsErrCode.Add("421", &quo

13、t;服务未就绪，关闭传输信道"); hsErrCode.Add("450", "要求的邮件操作未完成，邮箱不可用（例如，邮箱忙）"); hsErrCode.Add("550", "要求的邮件操作未完成，邮箱不可用（例如，邮箱未找到，或不可访问）"); hsErrCode.Add("451", "放弃要求的操作；处理过程中出错"); hsErrCode.Add("551", "用户非本地，请尝试<forward-path>&q

14、uot;); hsErrCode.Add("452", "系统存储不足，要求的操作未执行"); hsErrCode.Add("552", "过量的存储分配，要求的操作未执行"); hsErrCode.Add("553", "邮箱名不可用，要求的操作未执行（例如邮箱格式错误）"); hsErrCode.Add("432", "需要一个密码转换"); hsErrCode.Add("534", "认证机制过于简单

15、"); hsErrCode.Add("538", "当前请求的认证机制需要加密"); hsErrCode.Add("454", "临时认证失败"); hsErrCode.Add("530", "需要认证"); hsRigCode.Add("220", "服务就绪"); hsRigCode.Add("250", "要求的邮件操作完成"); hsRigCode.Add("251&q

16、uot;, "用户非本地，将转发向<forward-path>"); hsRigCode.Add("354", "开始邮件输入，以<CRLF>.<CRLF>结束"); hsRigCode.Add("221", "服务关闭传输信道"); hsRigCode.Add("334", "服务器响应验证Base64字符串"); hsRigCode.Add("235", "验证成功"); #e

17、ndregion #region Base64EnCode 字符串转换为base64码 / <summary> / 字符串转换为base64码 / </summary> / <param name="strValue"></param> / <returns></returns> private string Base64EnCode(string strValue) byte barray; barray = Encoding.Default.GetBytes(strValue); return Co

18、nvert.ToBase64String(barray); #endregion #region Base64DeCode base64码转换为普通字符 / <summary> / 将Base64字符串解码为普通字符串 / </summary> / <param name="strValue"></param> / <returns></returns> private string Base64DeCode(string strValue) byte barray; barray = Convert.

19、FromBase64String(strValue); return Encoding.Default.GetString(barray); #endregion #region MailToAdd 添加收件人 / <summary> / 添加收件人 / </summary> / <param name="varMailToAddress"></param> public void MailToAdd(string strMailToAddress) _listMailTo.Add(strMailToAddress); #en

20、dregion #region MailToAdd 添加一组收件人 / <summary> / 添加一组收件人 / </summary> / <param name="strMailAddress"></param> public void MailToAdd(string strMailAddress) foreach (string str in strMailAddress) MailToAdd(str); #endregion #region MailToClear 清空收件人 / <summary> /

21、清空收件人 / </summary> public void MailToClear() _listMailTo.Clear(); #endregion #region MailccToAdd 添加抄送人 / <summary> / 添加抄送人 / </summary> / <param name="strMialAddress"></param> public void MailccToAdd(string strMialAddress) _listMailccTo.Add(strMialAddress); #e

22、ndregion #region MailccToAdd 添加一组抄送人 / <summary> / 添加一组抄送人 / </summary> / <param name="strMailAddress"></param> public void MailccToAdd(string strMailAddress) foreach (string str in strMailAddress) MailccToAdd(str); #endregion #region MailccToClear 清空抄送人 / <summa

23、ry> / 清空抄送人 / </summary> public void MailccToClear() _listMailccTo.Clear(); #endregion #region AttachmentAdd 邮件添加附件 / <summary> / 邮件添加附件 / </summary> / <param name="strFilePath"></param> public void AttachmentAdd(string strFilePath) _listAttachments.Add(str

24、FilePath); #endregion #region AttachmentClear 清空邮件附件 / <summary> / 清空邮件附件 / </summary> public void AttachmentClear() _listAttachments.Clear(); #endregion #region GetFileStream 获取附件文件流 / <summary> / 获取附件文件流 / </summary> / <param name="strFilePath"></param>

25、; / <returns></returns> private string GetFileStream(string strFilePath) FileStream file = new FileStream(strFilePath, System.IO.FileMode.Open); byte byStream = new byteSystem.Convert.ToInt32(file.Length); file.Read(byStream, 0, byStream.Length); file.Close(); return (System.Convert.ToBa

26、se64String(byStream); #endregion #region SendStream 向SMTP服务器发送数据 / <summary> / 向SMTP服务器发送数据 / </summary> / <param name="strCmd"></param> / <returns></returns> private bool SendStream(string strCmd) byte SendBuffer; SendBuffer = Encoding.Default.GetBytes(

27、strCmd); try NetStream.Write(SendBuffer, 0, SendBuffer.Length); return true; catch (Exception ex) ErrMsg = "网络连接错误:" + ex.Message; return false; #endregion #region ReceiveStream 接收SMTP服务器返回数据 / <summary> / 接收SMTP服务器返回数据 / </summary> / <returns></returns> private str

28、ing ReceiveStream() int StreamSize; string ReturnStream = "" byte ReadBuffer = new byte1024; try StreamSize = NetStream.Read(ReadBuffer, 0, ReadBuffer.Length); if (StreamSize != 0) ReturnStream = Encoding.Default.GetString(ReadBuffer).Substring(0, StreamSize); catch (Exception ex) ErrMsg =

29、 "网络连接错误:" + ex.Message; return ReturnStream; #endregion #region CheckCommand 校验数据发送状态 / <summary> / 校验数据发送状态 / </summary> / <param name="strCmd"></param> / <returns></returns> private bool CheckCommand(string strCmd) if (SendStream(strCmd) str

30、ing strReturn = ReceiveStream(); if (strReturn = "") return false; string strReturnCode = strReturn.Substring(0, 3); if (hsRigCodestrReturnCode != null) return true; else if (hsErrCodestrReturnCode != null) ErrMsg += (strReturnCode + hsErrCodestrReturnCode.ToString(); ErrMsg += CRLF; else

31、ErrMsg += strReturn; return false; else return false; private bool CheckCommand(string strCmds) for (int i = 0; i < strCmds.Length; i+) if (CheckCommand(strCmdsi) continue; else return false; return true; #endregion #region SendMail 发送邮件 / <summary> / 发送邮件 / </summary> / <returns&g

32、t;</returns> private bool SendMail() /连接网络 try client = new TcpClient(_strSmtpServer, _intPort); catch (Exception ex) ErrMsg += ex.Message; return false; NetStream = client.GetStream(); /验证网络连接是否正确 if (hsRigCodeReceiveStream().Substring(0, 3) = null) ErrMsg += "网络连接失败" return false;

33、string SendCmdStrings; string SendCmdString; /进行SMTP验证 if (UserName != "") SendCmdStrings = new String4; SendCmdStrings0 = "EHLO " + _strSmtpServer + CRLF; SendCmdStrings1 = "AUTH LOGIN" + CRLF; SendCmdStrings2 = Base64EnCode(UserName) + CRLF; SendCmdStrings3 = Base64En

34、Code(PassWord) + CRLF; if (!CheckCommand(SendCmdStrings) return false; else SendCmdString = "HELO " + _strSmtpServer + CRLF; if (!CheckCommand(SendCmdString) return false; SendCmdString = "MAIL FROM:<" + _strMailFrom + ">" + CRLF; if (!CheckCommand(SendCmdString)

35、return false; for (int i = 0; i < _listMailTo.Count; i+) SendCmdString = "RCPT TO:<" + _listMailToi.ToString() + ">" + CRLF; if (!CheckCommand(SendCmdString) return false; SendCmdString = "DATA" + CRLF; if (!CheckCommand(SendCmdString) return false; /构造发送数据 Sen

36、dCmdString = "From:" + _strMailFromName + "<" + _strMailFrom + ">" + CRLF; SendCmdString += "To:<" + _listMailTo0 + ">" for (int i = 1; i < _listMailTo.Count; i+) SendCmdString += ",<" + _listMailToi.ToString() + ">

37、;," SendCmdString += CRLF; if (_listMailccTo.Count != 0) SendCmdString += "CC:" for (int i = 0; i < _listMailccTo.Count; i+) SendCmdString += "<" + _listMailccToi.ToString() + ">," SendCmdString += CRLF; if (_strCharSet = "") SendCmdString += &qu

38、ot;Subject:" + _strSubject + CRLF; else SendCmdString += "Subject:=?" + _strCharSet.ToUpper() + "?B?" + Base64EnCode(_strSubject) + "?=" + CRLF; SendCmdString += "X-Priority:" + Priority + CRLF; SendCmdString += "X-MSMail-Priority:" + Priority +

39、 CRLF; SendCmdString += "Importance:" + Priority + CRLF; SendCmdString += "X-Mailer: Huolx.Pubclass" + CRLF; SendCmdString += "MIME-Version: 1.0" + CRLF; if (_listAttachments.Count != 0) SendCmdString += "Content-Type: multipart/mixed;" + CRLF; SendCmdString +

40、= " boundary="=" + (_IsHtml ? "001_mail_part_line_01" : "002_mail_part_line_01") + "="" + CRLF + CRLF; if (_IsHtml) if (_listAttachments.Count = 0) SendCmdString += "Content-Type: multipart/alternative;" + CRLF;/内容格式和分隔符 SendCmdString += &q

41、uot; boundary="=001_mail_part_line_02="" + CRLF + CRLF; SendCmdString += "This is a multi-part message in MIME format." + CRLF + CRLF; else SendCmdString += "This is a multi-part message in MIME format." + CRLF + CRLF; SendCmdString += "-=001_mail_part_line_01

42、=" + CRLF; SendCmdString += "Content-Type: multipart/alternative;" + CRLF;/内容格式和分隔符 SendCmdString += " boundary="=001_mail_part_line_02="" + CRLF + CRLF; SendCmdString += "-=001_mail_part_line_02=" + CRLF; SendCmdString += "Content-Type: text/plain;&

43、quot; + CRLF; SendCmdString += (_strCharSet = "") ? (" charset="iso-8859-1"") : (" charset="" + _strCharSet.ToLower() + """) + CRLF; SendCmdString += "Content-Transfer-Encoding: base64" + CRLF + CRLF; SendCmdString += Base64EnCode

44、("邮件内容为HTML格式，请选择HTML方式查看") + CRLF + CRLF; SendCmdString += "-=001_mail_part_line_02=" + CRLF; SendCmdString += "Content-Type: text/html;" + CRLF; SendCmdString += (_strCharSet = "") ? (" charset="iso-8859-1"") : (" charset="" + _strCharSet.ToLower() + """) + CRLF; SendCmdString += "Content-Transfer-Encoding: base64" + CRLF + CRLF; SendCmdString += Base64EnCode(_strBody) + CRLF + CRLF; SendCmdString += "-=001_mail_part_line_02=-" + CRLF; else if (_listAttachments.Count != 0) S