转载自：http://www.cnblogs.com/mingmingruyuedlut/archive/2011/10/14/2212255.html
发送邮件所用的核心知识点
微软封装好的MailMessage类：主要处理发送邮件的内容（如：收发人地址、标题、主体、图片等等）
微软封装好的SmtpClient类：主要处理用smtp方式发送此邮件的配置信息（如：邮件服务器、发送端口号、验证方式等等）
SmtpClient主要进行了三层的封装：Socket --> TcpClient --> SmtpClient
具体代码请看如下所示：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Mail;
using System.Net.Mime;
using System.IO;
using System.Timers;
using System.Xml;
namespace MyEmailTest
{
class Program
{
static void Main(string[] args)
{
try
{
//smtp.163.com
string senderServerIp = "123.125.50.133";
//smtp.gmail.com
//string senderServerIp = "74.125.127.109";
//smtp.qq.com
//string senderServerIp = "58.251.149.147";
//string senderServerIp = "smtp.sina.com";
string toMailAddress = "mingmingruyuedlut@163.com";
string fromMailAddress = "mingmingruyuedlut@163.com";
string subjectInfo = "Test sending e_mail";
string bodyInfo = "Hello Eric, This is my first testing e_mail";
string mailUsername = "mingmingruyuedlut";
string mailPassword = ".........."; //发送邮箱的密码（）
string mailPort = "25";
string attachPath = "E:123123.txt; E:haha.pdf";
MyEmail email = new MyEmail(senderServerIp, toMailAddress, fromMailAddress, subjectInfo, bodyInfo, mailUsername, mailPassword, mailPort, false, false);
email.AddAttachments(attachPath);
email.Send();
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
}
public class MyEmail
{
private MailMessage mMailMessage; //主要处理发送邮件的内容（如：收发人地址、标题、主体、图片等等）
private SmtpClient mSmtpClient; //主要处理用smtp方式发送此邮件的配置信息（如：邮件服务器、发送端口号、验证方式等等）
private int mSenderPort; //发送邮件所用的端口号（htmp协议默认为25）
private string mSenderServerHost; //发件箱的邮件服务器地址（IP形式或字符串形式均可）
private string mSenderPassword; //发件箱的密码
private string mSenderUsername; //发件箱的用户名（即@符号前面的字符串，例如：hello@163.com，用户名为：hello）
private bool mEnableSsl; //是否对邮件内容进行socket层加密传输
private bool mEnablePwdAuthentication; //是否对发件人邮箱进行密码验证
///<summary>
/// 构造函数
///</summary>
///<param name="server">发件箱的邮件服务器地址</param>
///<param name="toMail">收件人地址（可以是多个收件人，程序中是以“;"进行区分的）</param>
///<param name="fromMail">发件人地址</param>
///<param name="subject">邮件标题</param>
///<param name="emailBody">邮件内容（可以以html格式进行设计）</param>
///<param name="username">发件箱的用户名（即@符号前面的字符串，例如：hello@163.com，用户名为：hello）</param>
///<param name="password">发件人邮箱密码</param>
///<param name="port">发送邮件所用的端口号（htmp协议默认为25）</param>
///<param name="sslEnable">true表示对邮件内容进行socket层加密传输，false表示不加密</param>
///<param name="pwdCheckEnable">true表示对发件人邮箱进行密码验证，false表示不对发件人邮箱进行密码验证</param>
public MyEmail(string server, string toMail, string fromMail, string subject, string emailBody, string username, string password, string port, bool sslEnable, bool pwdCheckEnable)
{
try
{
mMailMessage = new MailMessage();
mMailMessage.To.Add(toMail);
mMailMessage.From = new MailAddress(fromMail);
mMailMessage.Subject = subject;
mMailMessage.Body = emailBody;
mMailMessage.IsBodyHtml = true;
mMailMessage.BodyEncoding = System.Text.Encoding.UTF8;
mMailMessage.Priority = MailPriority.Normal;
this.mSenderServerHost = server;
this.mSenderUsername = username;
this.mSenderPassword = password;
this.mSenderPort = Convert.ToInt32(port);
this.mEnableSsl = sslEnable;
this.mEnablePwdAuthentication = pwdCheckEnable;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
///<summary>
/// 添加附件
///</summary>
///<param name="attachmentsPath">附件的路径集合，以分号分隔</param>
public void AddAttachments(string attachmentsPath)
{
try
{
string[] path = attachmentsPath.Split(';'); //以什么符号分隔可以自定义
Attachment data;
ContentDisposition disposition;
for (int i = 0; i < path.Length; i++)
{
data = new Attachment(path[i], MediaTypeNames.Application.Octet);
disposition = data.ContentDisposition;
disposition.CreationDate = File.GetCreationTime(path[i]);
disposition.ModificationDate = File.GetLastWriteTime(path[i]);
disposition.ReadDate = File.GetLastAccessTime(path[i]);
mMailMessage.Attachments.Add(data);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
///<summary>
/// 邮件的发送
///</summary>
public void Send()
{
try
{
if (mMailMessage != null)
{
mSmtpClient = new SmtpClient();
//mSmtpClient.Host = "smtp." + mMailMessage.From.Host;
mSmtpClient.Host = this.mSenderServerHost;
mSmtpClient.Port = this.mSenderPort;
mSmtpClient.UseDefaultCredentials = false;
mSmtpClient.EnableSsl = this.mEnableSsl;
if (this.mEnablePwdAuthentication)
{
System.Net.NetworkCredential nc = new System.Net.NetworkCredential(this.mSenderUsername, this.mSenderPassword);
//mSmtpClient.Credentials = new System.Net.NetworkCredential(this.mSenderUsername, this.mSenderPassword);
//NTLM: Secure Password Authentication in Microsoft Outlook Express
mSmtpClient.Credentials = nc.GetCredential(mSmtpClient.Host, mSmtpClient.Port, "NTLM");
}
else
{
mSmtpClient.Credentials = new System.Net.NetworkCredential(this.mSenderUsername, this.mSenderPassword);
}
mSmtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
mSmtpClient.Send(mMailMessage);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
}
}
要开启邮箱的SmTP服务。