C# 发送邮件

using System.Net.Mail;

using System.Net;

using System.Text;

protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {

            //实例化SmtpClient
            SmtpClient client = new SmtpClient("pop.qq.com", 25);
            //出站方式设置为NetWork
            client.DeliveryMethod = SmtpDeliveryMethod.Network;
            //smtp服务器验证并制定账号密码
            client.Credentials = new NetworkCredential("xxx@qq.com", "******");
            MailMessage message = new MailMessage();
            //设置优先级
            message.Priority = MailPriority.Normal;
            //设置收件方看到的邮件来源为:发送方邮件地址、来源标题、编码
            message.From = new MailAddress("xxx@qq.com", "xxx", Encoding.GetEncoding("gb2312"));
            //接收方
            message.To.Add("yyy@qq.com");
            //标题
            message.Subject = "This is 标题";
            message.SubjectEncoding = Encoding.GetEncoding("gb2312");
            //邮件正文是否支持HTML
            message.IsBodyHtml = true;
            //正文编码
            message.BodyEncoding = Encoding.GetEncoding("gb2312");
            message.Body = "<font color='red'>这是一封使用C#网页发送的电子邮件！请勿回复！测试</font><br/>";
            client.Send(message);
        }
        catch (System.Exception ex)
        {
            Response.Write(ex.Message);
        }

    }

//超时，默认100s

client.Timeout = 100000;

//附件列表

message.Attachments.Add(new Attachment("E:\\a.txt"));

webconfig 设置超时60s

<system.web>

<httpRuntime maxRequestLength="1000000" executionTimeout="60000" />

</system.web>