基于web的邮件发送，发送端要认证，如何写

Question

想写个简单的页面，有标题，内容，然后发送按钮发送到指定的邮箱即可
但发送的邮件服务器要求发送端认证的
代码中如何设置发送端认证这个属性
望实现过的大侠指点一下
谢谢

Answer 1

 private void btnNet_Click(object sender, EventArgs e)
        {
            try
            {
                MailAddress from = new MailAddress(txtFrom.Text);
                MailAddress to = new MailAddress(txtTo.Text);
                MailAddress cc = new MailAddress(txtCC.Text);
                System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(from, to);
                message.CC.Add(cc);
                message.Subject = txtSubject.Text;
                message.SubjectEncoding = Encoding.UTF8;
                message.Body = txtBody.Text;
                message.BodyEncoding = Encoding.UTF8;
                message.IsBodyHtml = (txtBodyFormat.Text.Trim() == "Text" ? false : true);                SmtpClient client = new SmtpClient(txtServer.Text);
                client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                if (this.txtUser.Text != "" && this.txtPassword.Text != "")
                {
                    client.Credentials = new System.Net.NetworkCredential(this.txtUser.Text, this.txtPassword.Text);--賬號，密碼
                }
                client.Send(message);
                MessageBox.Show("Mail Sent");            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

Answer 2

按照zhangandli的代码运行后得到“身份验证失败”的提示
该如何解决，是哪里出的问题

Answer 3

    public void SendMail()
    {          
        MailMessage mymail = new MailMessage();
        string strmailserver = ConfigurationSettings.AppSettings["MailIP"].ToString();  //邮箱服务器
        SmtpMail.SmtpServer = strmailserver;        bool flag = false;
     
   
                mymail.From = "***";
                mymail.To = "***";
                mymail.Subject = "***";
                mymail.Body = "***";
                 flag = ISsendMail(mymail);
            }
        }
        if (flag == true)
        {
            Response.Write("<script>alert('邮件发送成功！')</script>");
        }
        else
        {
            Response.Write("<script>alert('邮件发送失败！无法找到Email地址！')</script>");
        }
    }    public bool ISsendMail(MailMessage MailMes)
    {
        string strIsSend = ConfigurationSettings.AppSettings["IsSendMail"].ToString();
        if (strIsSend == "true")
        {
            try
            {
                SmtpMail.Send(MailMes);
                return true;
            }
            catch
            {
                return false;
            }
        }
        else
        {
            return false;
        }
       
    }