C#利用System.Net发送邮件（带 抄送、密送、附件、html格式的邮件）

net2.0后，C#可以利用System.Net发送邮件了。

代码整理如下：

　3. 增加IProcessMessage类，定义了一个消息方法，用于消息传递

/************************************** 
* <copyright file="SendEail.cs"> 
* Copyright(c)2014 LeeStudio All rights reserved. 
* CLR版本：4.0.30319.17929 
* 开发团队：欺心伴月个人工作室 
* 技术博客：http://www.cnblogs.com/lichunyang/ 
* 所属工程：LeeStudio.Basic 
* 创 建 者：Frank Lee 
* 修改时间：2014-02-20 11:20 
* </copyright> 
**************************************/

using System;
using System.Text;
using System.Net;
using System.Net.Mail;
using System.Net.Mime;

namespace LeeStudio.Basic
{
/// <summary> 
/// 邮件发送类 
/// </summary> 
public class SendEmail
{
private MailMessage mailMessage = new MailMessage(); //实例化一个邮件类

#region 构造函数 
/// <summary> 
/// 构造函数 
/// </summary> 
/// <param name="toAddresses">收件人地址（多个以,号分开）</param> 
/// <param name="fromAddress">发件人地址</param> 
/// <param name="title">主题</param> 
/// <param name="body">正文</param> 
public SendEmail(string toAddresses, string fromAddress, string title, string body)
: this(toAddresses, fromAddress, "", "", title, body, false)
{
}

/// <summary> 
/// 构造函数 
/// </summary> 
/// <param name="toAddress">收件人地址</param> 
/// <param name="fromAddress">发件人地址</param> 
/// <param name="toName">收件人名字</param> 
/// <param name="fromName">发件人姓名</param> 
/// <param name="title">主题</param> 
/// <param name="body">正文</param> 
/// <param name="isBodyHtml">正文是否为html格式</param> 
public SendEmail(string toAddress, string fromAddress, string toName, string fromName, string title, string body, bool isBodyHtml)
{
mailMessage.From = new MailAddress(fromAddress, fromName, Encoding.GetEncoding(936));
if (toName.Equals(""))
mailMessage.To.Add(toAddress);
else
mailMessage.To.Add(new MailAddress(toAddress, toName, Encoding.GetEncoding(936)));

mailMessage.Subject = title;
mailMessage.SubjectEncoding = Encoding.GetEncoding(936);

mailMessage.Body = body;
mailMessage.IsBodyHtml = isBodyHtml;
mailMessage.BodyEncoding = Encoding.GetEncoding(936);
}
#endregion

/// <summary> 
/// 设置SMTP，并且将邮件发送出去 
/// 所有参数都设置完成后再调用该方法 
/// </summary> 
/// <param name="password">发件人密码</param> 
/// <param name="smtpHost">SMTP服务器地址</param> 
public void SetSmtp(string password, string smtpHost)
{
SetSmtp(mailMessage.From.Address, password, smtpHost, 25, false, MailPriority.Normal);
}

/// <summary> 
/// 设置SMTP，并且将邮件发送出去 
/// 所有参数都设置完成后再调用该方法 
/// </summary> 
/// <param name="address">发件人地址（必须为真实有效的email地址）</param> 
/// <param name="password">发件人密码</param> 
/// <param name="smtpHost">SMTP服务器地址</param> 
/// <param name="smtpPort">SMTP服务器的端口</param> 
/// <param name="isEnableSsl">SMTP服务器是否启用SSL加密</param> 
/// <param name="priority">邮件的优先级</param> 
public void SetSmtp(string address, string password, string smtpHost, int smtpPort, bool isEnableSsl, MailPriority priority)
{
SmtpClient smtp = new SmtpClient();
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Credentials = new NetworkCredential(address, password);
smtp.Host = smtpHost;
smtp.Port = smtpPort;
smtp.EnableSsl = isEnableSsl;

mailMessage.Priority = priority;
smtp.Send(mailMessage); //发送邮件 
}

#region //设置邮件地址 
/// <summary> 
/// 设置更多收件人 
/// </summary> 
/// <param name="toAddresses">收件人地址</param> 
public void SetMoreToAddress(string toAddresses)
{
mailMessage.To.Add(toAddresses);
}

/// <summary> 
/// 设置更多收件人 
/// </summary> 
/// <param name="toAddresses">收件人地址</param> 
/// <param name="toName">收件人名字</param> 
public void SetMoreToAddress(string toAddress, string toName)
{
mailMessage.To.Add(new MailAddress(toAddress, toName, Encoding.GetEncoding(936)));
}

/// <summary> 
/// 设置抄送者（多个以,号分开） 
/// </summary> 
/// <param name="ccAddresses">抄送者地址</param> 
public void SetCarbonCopyFor(string ccAddresses)
{
mailMessage.CC.Add(ccAddresses);
}

/// <summary> 
/// 设置抄送者 
/// </summary> 
/// <param name="ccAddress">抄送者地址</param> 
/// <param name="ccName">抄送者名字</param> 
public void SetCarbonCopyFor(string ccAddress, string ccName)
{
mailMessage.Bcc.Add(new MailAddress(ccAddress, ccName, Encoding.GetEncoding(936)));
}

/// <summary> 
/// 设置密送者（多个以,号分开） 
/// </summary> 
/// <param name="bccAddresses">密送者</param> 
public void SetBlindCarbonCopyFor(string bccAddresses)
{
mailMessage.Bcc.Add(bccAddresses);
}

/// <summary> 
/// 设置密送者 
/// </summary> 
/// <param name="bccAddress">密送者</param> 
/// <param name="bccName">密送者名字</param> 
public void SetBlindCarbonCopyFor(string bccAddress, string bccName)
{
mailMessage.Bcc.Add(new MailAddress(bccAddress, bccName, Encoding.GetEncoding(936)));
}
#endregion

#region 添加附件 
/// <summary> 
/// 添加附件（自动识别文件类型） 
/// </summary> 
/// <param name="fileName">单个文件的路径</param> 
public void Attachments(string fileName)
{
mailMessage.Attachments.Add(new Attachment(fileName));
}

/// <summary> 
/// 添加附件（默认为富文本RTF格式） 
/// </summary> 
/// <param name="fileName">单个文件的路径</param> 
public void AttachmentsForRTF(string fileName)
{
mailMessage.Attachments.Add(new Attachment(fileName, MediaTypeNames.Application.Rtf));
}
#endregion
}
}

调用是按照需求，自由设置参数。

using LeeStudio.Basic;

private void SendEmail()
{
#region 最简设置 
//SendEmail se = new SendEmail("*****@****.com", "****@163.com", "title", "body"); 
//se.SetSmtp("password", "smtp.163.com"); //必须在所有参数设置完后调用此方法 
#endregion

#region 完全设置 
//string toAddresses = "***@**.**,***@**.**"; 
//string toNames = "frank,lee";

//SendEmail se = new SendEmail("to@**.**", "from@**.**", "toname", "fromname","title", "body", false); 
//se.SetMoreToAddress("to@**.**", "toName"); 
//se.SetCarbonCopyFor("cc@**.**"); 
//se.SetBlindCarbonCopyFor("bcc@**.**");

//string filePath = Request.PhysicalApplicationPath + "/file/SendEmail.txt"; 
//se.Attachments(filePath); 
//filePath = Request.PhysicalApplicationPath + "/file/RTF文件.docx"; 
//se.AttachmentsForRTF(filePath); 
//se.SetSmtp("email", "password", "smtp", 25, true, System.Net.Mail.MailPriority.Normal); //必须在所有参数设置完后调用此方法 
#endregion
}

遗留问题：

当有多个收件人/抄送者/密送者时，如何快速处理？之前的做法是让用户输入字符串，再将字符串一一对应匹配，代码如下：

/// <summary>  
/// 将邮件地址和名称加入到锯齿数组中  
/// </summary>  
/// <param name="addrs">邮件地址（多个以,号分开）</param>  
/// <param name="names">名称（多个以,号分开）</param>  
/// <returns>地址和名称数组</returns>  
private string[][] SetNameList(string addrs, string names)
{
    string[][] result = new string[2][];

    string[] addr = addrs.Split(',');
    string[] name = names.Split(',');
    result[0] = new string[addr.Length];
    result[1] = new string[name.Length];

    for (int i = 0; i < addr.Length; i++)
        result[0][i] = addr[i];
    for (int i = 0; i < name.Length; i++)
        result[1][i] = name[i];

    return result;
}

首先这个方法就很奇葩，其次，只要用户输入的个数不对应，又要做一堆的异常处理。