<h2>
 发送电子邮件演示
 </h2>
 <table cellpadding="0" cellspacing="0" border="0" style="font-family: 宋体, Arial, Helvetica, sans-serif;
 font-size: 15px; width: 411px;">
 <tr>
 <td class="style5">
 邮箱地址：
 </td>
 <td class="style6">
 <asp:TextBox ID="tb_Email" runat="server" Width="269px"></asp:TextBox>
 </td>
 </tr>
 <tr>
 <td class="style5">
 抄送至：
 </td>
 <td class="style6">
 <asp:TextBox ID="tb_cc" runat="server" Width="268px"></asp:TextBox>
 </td>
 </tr>
 <tr>
 <td class="style5">
 邮件主题：
 </td>
 <td class="style6">
 <asp:TextBox ID="tb_Subject" runat="server" Width="268px"></asp:TextBox>
 </td>
 </tr>
 <tr>
 <td class="style5">
 邮件内容：
 </td>
 <td class="style6">
 <asp:TextBox ID="tb_Body" runat="server" Height="63px" TextMode="MultiLine" Width="266px"></asp:TextBox>
 </td>
 </tr>
 <tr>
 <td class="style5">
 添加附件：
 </td>
 <td class="style6">
 <asp:FileUpload ID="tb_Attachment" runat="server" Width="265px" />
 </td>
 </tr>
 <tr>
 <td align="right" colspan="2">
 <asp:Button ID="btn_SendEmail" runat="server" Text="发送邮件" OnClick="btn_SendEmail_Click" />
 </td>
 </tr>
 </table>

protected void btn_SendEmail_Click(object sender, EventArgs e)
 {
 //声明一个Mail对象
 MailMessage mymail = new MailMessage();
 //发件人地址
 //如是自己，在此输入自己的邮箱
 mymail.From = new MailAddress("[email protected]");
 //收件人地址
 mymail.To.Add(new MailAddress(tb_Email.Text));
 //邮件主题
 mymail.Subject = tb_Subject.Text;
 //邮件标题编码
 mymail.SubjectEncoding = System.Text.Encoding.UTF8;
 //发送邮件的内容
 mymail.Body = tb_Body.Text;
 //邮件内容编码
 mymail.BodyEncoding = System.Text.Encoding.UTF8;
 //添加附件
 Attachment myfiles = new Attachment(tb_Attachment.PostedFile.FileName);
 mymail.Attachments.Add(myfiles);
 //抄送到其他邮箱
 mymail.CC.Add(new MailAddress(tb_cc.Text));
 //是否是HTML邮件
 mymail.IsBodyHtml = true;
 //邮件优先级
 mymail.Priority = MailPriority.High;
 //创建一个邮件服务器类
 SmtpClient myclient = new SmtpClient();
 myclient.Host = "SMTP.163.com"; 
 //SMTP服务端口
 myclient.Port = 25;
 //验证登录
 myclient.Credentials = new NetworkCredential("@@@@@@", "*****");//"@"输入有效的邮件名, "*"输入有效的密码
 myclient.Send(mymail);
 }