C#使用System.Net.Mail类实现邮件发送

第C#使用System.Net.Mail类实现邮件发送有些SMTP服务器要求在代表客户端发送电子邮件前验证客户端的身份。当此SmtpClient对象应该使用当前登录用户的默认凭据进行身份验证（如果服务器要求）时，请将此属性设置为true。对于客户端应用程序，这是在大多数情况下都需要的行为。也可以使用应用程序和计算机配置文件指定凭据信息。有关更多信息，请参见mailSettings元素（网络设置）。

如果UseDefaultCredentials属性设置为false，则连接到服务器时会将Credentials属性中设置的值用作凭据。如果UseDefaultCredentials属性设置为false并且尚未设置Credentials属性，则将邮件以匿名方式发送到服务器。UseDefaultCredentials的默认值为false。

如果提供用于基本身份验证的凭据，则凭据将以明文形式发送到服务器。这可能会产生安全问题，因为凭据可以被他人看见从而加以利用。但是向163的邮箱发送邮件是必须要带上发送者的凭据信息，否则邮件是发送不出去的。

SmtpClient也可以这样建立:SmtpClientclient=newSmtpClient(smtp_server)，因为邮件发送服务器的默认端口是25。

1、QQ邮箱向163邮箱发送邮件

privatestaticvoidTimeEvent(objectsource,ElapsedEventArgse)

stringsmtp_server="";

intport=25;

stringmail_from="***from_mail_username***@";

stringsender="***from_mail_username***";

stringmail_to="***to_mail_username***@163.com";

stringreceiver="***to_mail_username***@";

stringsubject="TitleTest"

stringbody="ContentTest";

SendEmail(smtp_server,port,mail_from,sender,mail_to,receiver,subject,body);

catch(Exceptionex)

MessageBox.Show(ex.Message);

publicstaticvoidSendEmail(stringsmtp_server,intport,stringmail_from,stringsender,stringmail_to,stringreceiver,stringsubject,stringbody)

MailAddressfrom=newMailAddress(mail_from,sender);

MailAddressto=newMailAddress(mail_to,receiver);

MailMessagemessage=newMailMessage(from,to);

message.BodyEncoding=Encoding.UTF8;

message.IsBodyHtml=true;

message.Subject=subject;

message.Body=body;

SmtpClientclient=newSmtpClient(smtp_server,port);

client.Credentials=newNetworkCredential("***from_mail_username***@","***pwd***");

client.Send(message);

}

2、163邮箱向163邮箱发送邮件

privatestaticvoidTimeEvent(objectsource,ElapsedEventArgse)

stringsmtp_server="";

intport=25;

stringmail_from="***from_mail_username***@163.com";

stringsender="***from_mail_username***";

stringmail_to="***to_mail_username***@163.com";

stringreceiver="***to_mail_username***";

stringsubject="TitleTest"

stringbody="ContentTest";

SendEmail(smtp_server,port,mail_from,sender,mail_to,receiver,subject,body);

catch(Exceptionex)

MessageBox.Show(ex.Message);

publicstaticvoidSendEmail(stringsmtp_server,intport,stringmail_from,stringsender,stringmail_to,stringreceiver,stringsubject,stringbody)

MailAddressfrom=newMailAddress(mail_from,sender);

MailAddressto=newMailAddress(mail_to,receiver);

MailMessagemessage=newMailMessage(from,to);

message.BodyEncoding=Encoding.UTF8;

message.IsBodyHtml=true;

message.Subject=subject;

message.Body=body;

SmtpClientclient=newSmtpClient(smtp_server);

client.Credentials=newNetworkCredential("***from_mail_username***@163.com","***pwd***");

client.Send(message);

}

3、163邮箱向QQ邮箱发送邮件

privatestaticvoidTimeEvent(objectsource,ElapsedEventArgse)

stringsmtp_server="";

intport=25;

stringmail_from="***from_mail_username***@163.com";

stringsender="***from_mail_username***";

stringmail_to="***to_mail_username***@";

stringreceiver="***to_mail_username***";

stringsubject="TitleTest"

stringbody="ContentTest";

SendEmail(smtp_server,port,mail_from,sender,mail_to,receiver,subject,body);

catch(Exceptionex)

MessageBox.Show(ex.Message);

publicstaticvoidSendEmail(stringsmtp_server,intport,stringmail_from,stringsender,stringmail_to,stringreceiver,stringsubject,stringbody)

MailAddressfrom=newMailAddress(mail_from,sender);

MailAddressto=newMailAddress(mail_to,receiver);

MailMessagemessage=newMailMessage(from,to);

message.BodyEncoding=Encoding.UTF8;

message.IsBodyHtml=true;

message.Subject=subject;

message.Body=body;

SmtpClientclient=newSmtpClient(smtp_server);

client.Credentials=newNetworkCredential("***from_mail_username***@163.com","***pwd***");

client.Send(message);

}

4、QQ邮箱向QQ邮箱发送邮件

privatestaticvoidTimeEvent(objectsource,ElapsedEventArgse)

stringsmtp_server="";

intport=25;

stringmail_from="***from_mail_username***@";

stringsender="***from_mail_username***";

stringmail_to="***to_mail_username***@";

stringreceiver="***to_mail_username***";

stringsubject="TitleTest"

stringbody="ContentTest";

SendEmail(smtp_server,port,mail_from,sender,mail_to,receiver,subject,body);

catch(Exceptionex)

MessageBox.Show(ex.Message);

publicstaticvoidSendEmail(stringsmtp_server,intport,stringmail_from,stringsender,stringmail_to,stringreceiver,stringsubject,stringbody)

MailAddressfrom=newMailAddress(mail_from,sender);

MailAddressto=newMailAddress(mail_to,receiver);

MailMessagemessage=newMailMessage(from,to);

message.BodyEncoding=Encoding.UTF8;

message.IsBodyHtml=true;

message.Subject=subject;