POP协议-Post Office Protocol,现在常用的是第三版，简称POP3,默认端口号为110。通过POP3,客户机登录服务器后，可以对自己的邮件进行删除或下载，下载后，电子邮件客户端软件就可以在本地对邮件进行处理，Windows操作系统默认安装的Outlook Express就采用这种工作方式。
实际上，收发邮件使用了两种协议，一种是TCP，用于收发数据；另一种是POP3，用于解析传送的命令。
POP protocol -Post Office Protocol, now commonly used is the third version, referred to as POP3, the default port number is 110. After POP3, the client is able to delete or download its own mail after logging on to the server. After downloading, the email client software can handle the mail locally, and the Outlook Express, which is installed by the Windows operating system by default, uses this mode of work.
Actually, there are two protocols for sending and receiving mail, one is TCP, which is used for sending and receiving data, the other is POP3, which is used to parse the command transmitted. (2018-04-02, C#, 44KB, 下载2次)
利用System.Web.Mail这个名称空间.在这个名字空间下，有一个专门使用SMTP协议来发送邮件的类：SmtpMail,它已能满足最普通的发送邮件的需求。这个类只有一个自己的公共函数--Send()和一个公共属性—SmtpServer，您必须通过SmtpServer属性来指定发送邮件的服务器的名称（或IP地址）,然后再调用Send()函数来发送邮件。您可以在Send函数的参数MailMessage对象中设置邮件的相关属性，如优先级、附件等等。除了以MailMessage对象为参数（如上述代码），Send函数还可以简单的直接以邮件的4个主要信息（from，to，subject，messageText）作为字符串参数来调用。
The use of System.Web.Mail namespace. In the name space, there is a special SMTP protocol used to send the message class: SmtpMail, it has been able to send messages to meet the most common needs. This class is only one of their public functions- Send () and a public property-SmtpServer, you must SmtpServer attribute to specify the sending mail server' s name (or IP address), and then call the Send () function to send a message. Send function, you can set the parameters of MailMessage object mail-related properties, such as priority, accessories and more. In addition to the MailMessage object as an argument (such as the above code), Send function, you can simply e-mail directly to the 4 key messages (from, to, subject, messageText) as a string parameter to call. (2011-05-27, C#, 50KB, 下载5次)