How to triggered mail automatically for every 3 days up to 3 times

I am working on Leave Management system, it is my company internal project. For this i placed fields like leave from date, to date, reporting manager submit button in leave management form, user enter these fields and click submit button mail(To: Reporting Manager, Cc: HR) goes to reporting manager from user(who is person leave applied) account, up to this working fine.

Now i got new requirement, User enter the leave management fields and submitted(user applying leave), this leave request goes to his reporting manager. Reporting manager not approved user leave request up to 3 days, that time the mail will triggered automatically for 3 every days once, up to 3 times from user mail account.

For example Today(21-08-2013) i applied leave, leave request goes to my reporting manager from my my mail account while applying time. my reporting manager not approved my leave request up to 3 days means 24-08-2013, this date mail should be send automatically from my account to reporting manager account, he not approved 24-08-2013 date also, again mail triggered automatically from my account to reporting manager account in 27-08-2013, if he not approved in 27-08-2013 also, mail triggered in 30-08-2013, even 28-08-2013 also not approved mail triggered automatically to my HR mail account(applying leave request time Cc mail goes HR).

Below the code in submit button in Leave management form:

 protected void BtnApplyLeave_Click(object sender, EventArgs e) { if (ddlleavetype.SelectedIndex == 0) { lblerrmsg.Text = "Please select Leavetype"; lblerrmsg.Visible = true; } else if (txtmbno.Text == "") { lblerrmsg.Text = "Please Enter MobileNO"; lblerrmsg.Visible = true; } else if (txtfromdate.Text == "") { lblerrmsg.Text = "please Select From date"; lblerrmsg.Visible = true; } else if (txttodate.Text == "") { lblerrmsg.Text = "please Select todate"; lblerrmsg.Visible = true; } else if (txtReasonleave.Text == "") { lblerrmsg.Text = "Please Enter Reason for Leave"; lblerrmsg.Visible = true; } else { string username = Session["logUser"].ToString(); if (ddlleavetype.SelectedValue == "Earned Leave") { try { OleDbCommand com = new OleDbCommand("update IND_EMP_LEAVES set leavefromdate = to_date('" + txtfromdate.Text + "','dd/MM/yyyy'), leavetodate = to_date('" + txttodate.Text + "','dd/MM/yyyy'), MBNO = '" + txtmbno.Text + "', NOOFDAYSAPPL = '" + txtleavedays.Text + "', LEAVETYPE = '" + ddlleavetype.SelectedValue + "', REASONFORLEAVE = '" + txtReasonleave.Text + "', STATUS = '" + "null" + "' where Username ='" + username + "'", DbConnection); DbConnection.Open(); com.ExecuteNonQuery(); DbConnection.Close(); } catch (Exception ex) { ex.ToString(); } } else if (ddlleavetype.SelectedValue == "Sick Leave") { try { OleDbCommand com = new OleDbCommand("update IND_EMP_LEAVES set leavefromdate = to_date('" + txtfromdate.Text + "','dd/MM/yyyy'), leavetodate = to_date('" + txttodate.Text + "','dd/MM/yyyy'), MBNO = '" + txtmbno.Text + "', NOOFDAYSAPPL = '" + txtleavedays.Text + "', LEAVETYPE = '" + ddlleavetype.SelectedValue + "', REASONFORLEAVE = '" + txtReasonleave.Text + "', STATUS = '" + "null" + "' where Username ='" + username + "'", DbConnection); DbConnection.Open(); com.ExecuteNonQuery(); DbConnection.Close(); } catch(Exception ex) { ex.ToString(); } } else if (ddlleavetype.SelectedValue == "LOP") { try { OleDbCommand com = new OleDbCommand("update IND_EMP_LEAVES set leavefromdate = to_date('" + txtfromdate.Text + "','dd/MM/yyyy'), leavetodate = to_date('" + txttodate.Text + "','dd/MM/yyyy'), MBNO = '" + txtmbno.Text + "', NOOFDAYSAPPL = '" + txtleavedays.Text + "', LEAVETYPE = '" + ddlleavetype.SelectedValue + "', REASONFORLEAVE = '" + txtReasonleave.Text + "', STATUS = '" + "null" + "' where Username ='" + username + "'", DbConnection); DbConnection.Open(); com.ExecuteNonQuery(); DbConnection.Close(); } catch (Exception ex) { ex.ToString(); } } try { string subject = "Reg: Leave Request"; string datefrom = txtfromdate.Text; string dateto = txttodate.Text; string msg = txtReasonleave.Text; DbConnection.Open(); OleDbCommand cmd = new OleDbCommand("select EMP_NAME, REPT_MGR, hr from EMP_HIERARCHY where username ='" + username + "'", DbConnection); OleDbDataReader dr = cmd.ExecuteReader(); while (dr.Read()) { string ename = dr[0].ToString(); string rep_mgr = dr[1].ToString(); string hr_mgr = dr[2].ToString(); Session["emp"] = ename; Session["mgr"] = rep_mgr; Session["hr"] = hr_mgr; } dr.Close(); string emp = Session["emp"].ToString(); OleDbCommand cmd7 = new OleDbCommand("select M.OFFICIAL_EMAIL, L.pwd from EMP_MASTER M, emplogin L where L.username = '" + username + "' and M.username = L.username", DbConnection); OleDbDataReader dr1 = cmd7.ExecuteReader(); while (dr1.Read()) { string frommail = dr1[0].ToString(); string frompwd = dr1[1].ToString(); Session["from"] = frommail; Session["pwd"] = frompwd; } dr1.Close(); string mgr = Session["mgr"].ToString(); string hr = Session["hr"].ToString(); OleDbCommand cmd2 = new OleDbCommand("select OFFICIAL_EMAIL from emp_master where emp_name = '" + mgr + "'", DbConnection); OleDbDataReader dr2 = cmd2.ExecuteReader(); while (dr2.Read()) { string rep_to = dr2[0].ToString(); Session["to"] = rep_to.ToString(); } dr2.Close(); OleDbCommand cmd3 = new OleDbCommand("select OFFICIAL_EMAIL from emp_master where emp_name = '" + hr + "'", DbConnection); OleDbDataReader dr3 = cmd3.ExecuteReader(); while (dr3.Read()) { string hr_to = dr3[0].ToString(); Session["Cc"] = hr_to.ToString(); } dr3.Close(); string body = string.Concat("I would like to apply '" + ddlleavetype.SelectedValue + "' from ", datefrom, " to ", dateto, System.Environment.NewLine, "Reason: ", msg); string from = Session["from"].ToString(); string pwd = Session["pwd"].ToString(); string to = Session["to"].ToString(); string Cc = Session["Cc"].ToString(); var smtp = new System.Net.Mail.SmtpClient(); { smtp.Host = "smtp.gmail.com"; smtp.Port = 587; smtp.EnableSsl = true; smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network; smtp.Credentials = new NetworkCredential(from, pwd); smtp.Timeout = 20000; } //smtp.Send(from, to, subject, body); // Instantiate a new instance of MailMessage MailMessage mMailMessage = new MailMessage(); // Set the sender address of the mail message mMailMessage.From = new MailAddress(from); // Set the recepient address of the mail message mMailMessage.To.Add(new MailAddress(to)); // Check if the bcc value is null or an empty string //if ((bcc != null) && (bcc != string.Empty)) //{ // // Set the Bcc address of the mail message // mMailMessage.Bcc.Add(new MailAddress(bcc)); //} // Check if the cc value is null or an empty value if ((Cc != null) && (Cc != string.Empty)) { // Set the CC address of the mail message mMailMessage.CC.Add(new MailAddress(Cc)); } // Set the subject of the mail message mMailMessage.Subject = subject; // Set the body of the mail message mMailMessage.Body = body; // Set the format of the mail message body as HTML mMailMessage.IsBodyHtml = true; // Set the priority of the mail message to normal mMailMessage.Priority = MailPriority.Normal; // Instantiate a new instance of SmtpClient //SmtpClient smtp = new SmtpClient(); // Send the mail message smtp.Send(mMailMessage); ScriptManager.RegisterStartupScript(this, GetType(), "success", "alert('Leave Request sent Successfully');", true); // Session.Clear(); } catch (Exception ex) { ex.ToString(); } } }