How to create Emailer

Question

Hi Everyone. I want to create Emailer. In this Emailer send mail dynamically. Mailer get the LoginId and password retrieve from database and BCC ID also get from data base
Each id send 50 mail on in again and again change Login id and next BCC ID send the mail.. I am doing some work this project bt i dnt get Result Still.
Please help me

 using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Net.Mail;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.IO;

public partial class Default2 : System.Web.UI.Page
{
   
    int t = 0;
    ArrayList email_list = new ArrayList();
    int i = 0;
    
    protected void Page_Load(object sender, EventArgs e)
    {
    }
    public void EmailId()
    {
        t = t + 1;
        string UserID;
        string Password;
        SqlDataAdapter da;
        DataTable datatable;
        using (SqlConnection con = new SqlConnection("Data Source=GLASSXP;Initial Catalog=Emailer;Integrated Security=True;Pooling=False"))
        {
            SqlCommand cmd = new SqlCommand("select UserID,Password from Login where Id='" + t + "'", con);
            da = new SqlDataAdapter(cmd);
            datatable = new DataTable();
            da.Fill(datatable);
            UserID = Convert.ToString(datatable.Rows[0]["UserID"]);
            Password = Convert.ToString(datatable.Rows[0]["Password"]);
        }
    }
    protected void btnSendEmail_Click(object sender, EventArgs e)
    {
            EmailId();
            DB dB = new DB();
            System.Collections.Generic.List<string> listEmailIds = dB.GetEmailID();
            foreach (string email in listEmailIds)
            {
                {

                    MailMessage MyMailMessage = new MailMessage();
                    MyMailMessage.From = new MailAddress(UserID);
                    MyMailMessage.Bcc.Add(txtMail.Text);
                    MyMailMessage.IsBodyHtml = true;
                    MyMailMessage.Bcc.Add(email);
                    MyMailMessage.Body = txtbody.Text;
                    MyMailMessage.Subject = txtsubject.Text;
                    MyMailMessage.Priority = MailPriority.Normal;
                    System.Net.NetworkCredential mailAuthentication = new System.Net.NetworkCredential(UserID, Password);
                    System.Net.Mail.SmtpClient mailClient = new System.Net.Mail.SmtpClient("smtp.gmail.com", 587);
                    mailClient.EnableSsl = true;
                    mailClient.UseDefaultCredentials = false;
                    mailClient.Credentials = mailAuthentication;
                    mailClient.Send(MyMailMessage);
                    try
                    {
                        mailClient.Send(MyMailMessage);
                    }
                    catch (Exception ex)
                    {

                    }
                }
                errorLbl.Visible = true;
                errorLbl.Text = "mail sent";
            }
        }
    }