如何一键分别向多个收件人发送电子邮件

Question

我有一个邮件程序，我想在其中向多个收件人发送邮件。收件人可以来自数据库或 Excel 工作表。这是代码：

  protected void btnSubmit_Click(object sender, EventArgs e)
    {

        GetAllRecipient();


        Msg = null;
        ClientScript.RegisterStartupScript(GetType(), "alert", "alert('Email sent.');", true);

    }
  public void SendHTMLMail()
    {


       StreamReader reader = new StreamReader(Server.MapPath("~/one.html"));
        string readFile = reader.ReadToEnd();
        Regex regx = new Regex("(?<!src=\")http(s)?://([\\w+?\\.\\w+])+([a-zA-Z0-9\\~\\!\\@\\#\\$\\%\\^\\&amp;\\*\\(\\)_\\-\\=\\+\\\\\\/\\?\\.\\:\\;\\'\\,]*([a-zA-Z0-9\\?\\#\\=\\/]){1})?", RegexOptions.IgnoreCase);
        string output = regx.ToString();
        output = readFile;

        Msg.Body = output.ToString();
        Msg.IsBodyHtml = true;
        int i = 0;
        string username = Server.UrlEncode(this.txtUsername.Text);
        output = regx.Replace(output, new MatchEvaluator((match) =>
        {

            var url = Uri.EscapeDataString(match.Value.ToString());
            url = url.Replace("%3F", "&").Replace("%3D", "=");
            return $"http://localhost4654/two?sender={username}&link={url}&mailer_id={i}";
        }));

        Msg.From = new MailAddress(txtUsername.Text);
        Msg.Subject = null;

        smtp.Host = "smtp.gmail.com";
        smtp.Port = 587;
        smtp.UseDefaultCredentials = false;
        smtp.Credentials = new System.Net.NetworkCredential(txtUsername.Text, txtpwd.Text);
        smtp.EnableSsl = true;
    }
    public void GetAllRecipient()
    {
        if (RadioButton1.Checked)
        {
            SqlCommand cmd = new SqlCommand();
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "SELECT address FROM address1";
            cmd.Connection = sql;
            DataTable dt = new DataTable();
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            sql.Open();
            da.Fill(dt);
            sql.Close();

                for (int a = 0; a < dt.Rows.Count; a++)
                {
                foreach (DataRow row in dt.Rows)
                {
                    Msg.To.Add(row["address"].ToString());
                   SendHTMLMail();

                }
            }
        }

        else if (RadioButton2.Checked)
        {
            string connectionString = "";
            if (FileUpload1.HasFile)
            {
                string fileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
                string fileExtension = Path.GetExtension(FileUpload1.PostedFile.FileName);
                string fileLocation = Server.MapPath("~/App_Data/" + fileName);
                FileUpload1.SaveAs(fileLocation);

                if (fileExtension == ".xls")
                {

                    connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileLocation + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";
                }
                else if (fileExtension == ".xlsx")
                {
                    connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileLocation + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
                }
                OleDbConnection con = new OleDbConnection(connectionString);
                OleDbCommand cmd = new OleDbCommand();
                cmd.CommandType = System.Data.CommandType.Text;
                cmd.Connection = con;
                OleDbDataAdapter dAdapter = new OleDbDataAdapter(cmd);
                DataTable dt = new DataTable();
                con.Open();
                DataTable dtExcelSheetName = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
                string getExcelSheetName = dtExcelSheetName.Rows[0]["Table_Name"].ToString();
                cmd.CommandText = "SELECT address FROM [" + getExcelSheetName + "]";
                dAdapter.SelectCommand = cmd;
                dAdapter.Fill(dt);
                con.Close();

                for (int a = 0; a < dt.Rows.Count; a++)
                {
                    foreach (DataRow row in dt.Rows)
                    {
                        Msg.To.Add(row["address"].ToString());                       
                        SendHTMLMail();
                        smtp.Send(Msg);

                    }
                }
            }
        }
        else if (RadioButton3.Checked)
        {
            if (FileUpload2.HasFile)
            {

                string fileName = Path.GetFileName(FileUpload2.PostedFile.FileName);

                string fileLocation = Server.MapPath("~/App_Data/" + fileName);
                FileUpload2.SaveAs(fileLocation);
                StreamReader sr = new StreamReader(fileLocation);

                String line = sr.ReadToEnd();
                string[] toAddressArray;
                toAddressArray = line.Split(new char[] { ' ' });
                foreach (string a in toAddressArray)
                {
                    Msg.To.Add(a);

                }
            }
        }

    }

我面临的问题是 - 当我发送邮件时，它会在同一封邮件中发送给所有收件人，而不是单独发送。我怎样才能分开发送邮件，以便没有两个收件人互相认识。 此外，在我作为邮件正文发送的 HTML 页面中，有一些链接。当收件人单击任何链接时，我将在文本框“rep.text”中检索他的邮件 ID。因此，即使单击链接的人是第 4 位或第 5 位，我也会从收件人列表中获取姓氏。当我使用密件抄送时也会发生这种情况。

Answer 1

使用 Msg.Bcc.Add(sample@sample.com); 代替 Msg.To.Add(sample@sample.com);

See here

Answer 2

public static void SendEMail(string to, string subject, string body)
{
    SmtpClient smtpClient = new SmtpClient("smtp.mail.yahoo.com", 587);

    smtpClient.EnableSsl = true;
    smtpClient.UseDefaultCredentials = false;
    smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;

    smtpClient.Credentials = new NetworkCredential("my@com.pl", "12345!");

    MailMessage mailMessage = new MailMessage("\"" + Info.SiteName + "\" <" + Info.EMail + ">", "recipient1@gmail.com");

    mailMessage.Bcc.Add("recipient2@gmail.com");
    mailMessage.Bcc.Add("recipient3@gmail.com");
    mailMessage.Bcc.Add("recipient4@gmail.com");
    mailMessage.Bcc.Add("recipient5@gmail.com");
    mailMessage.Bcc.Add("recipient6@gmail.com");

    mailMessage.IsBodyHtml = true;

    mailMessage.Priority = MailPriority.High;

    mailMessage.Body = body;
    mailMessage.BodyEncoding = System.Text.Encoding.UTF8;
    mailMessage.Subject = subject;
    mailMessage.SubjectEncoding = System.Text.Encoding.UTF8;

    smtpClient.Send(mailMessage);
}

Answer 3

我认为我为你编写代码不会帮助你学习。此外，您遇到的问题似乎与编程语言无关，而是程序为实现其目标所需采取的逻辑步骤。

在开始编写代码之前，最好先写下这些步骤。

你最好把这个任务分解成小块的代码。

根据我从您的代码中可以看出，用户在表单上填写了他们的详细信息，以便向收件人列表发送电子邮件。

我已将步骤分解为不同的方法，希望对您有所帮助。在每个方法中填写它需要做的事情，仅此而已。确保每个步骤都有效，然后再进行下一步。我认为您拥有执行此操作的大部分代码，它只需要重组。

protected void btnSubmit_Click(object sender, EventArgs e)
{
    string user = GetUserDetails();
    List<string> recipients = GetAllRecipient();
    string html = GetHtmlTemplate();
    foreach (var recipient in recipients)
    {
        html = html.Replace("<<SOME TAG>>", recipient);
        SendEmail(recipient, html);
    }
}

public string GetUserDetails()
{
    return txtUsername.Text;
}

public List<string> GetAllRecipient()
{
    //TODO: Get all your recipient from database or excel
    //e,g, 
    return new List<string>() {"someemail@address.com", "anotheremail@address.com"};
}

public void SendEmail(string recipient, string html)
{
    //TODO: Send the email
}

我可以确定的步骤是： 用户 - 点击按钮

• 第一步：获取用户详细信息
• 第二步：获取所有收件人
• 第三步：获取Html模板
• 第 4 步：对于每个收件人 => 更新 html 模板 唯一链接并发送电子邮件。