How to Implement Reminder mail with help of asp.net with example

How to Implement Reminder mail with help of asp.net with example

Default.aspx=>
<%@ Page Language="C#" AutoEventWireup="true" Async="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Send Mail" />

Default.aspx.cs=>
using System.Web.UI.WebControls.WebParts;
 using System.Web.UI.HtmlControls;
 using System.ComponentModel;// for backgroundworker class
 using System.Net;
 using System.Net.Mail;
 using System.Threading;
 public partial class _Default : System.Web.UI.Page 
{
     BackgroundWorker bw;
     protected void Page_Load(object sender, EventArgs e)
     {
         bw = new BackgroundWorker();
         bw.DoWork+=new DoWorkEventHandler(bw_DoWork);
         bw.WorkerSupportsCancellation = true;
         bw.WorkerReportsProgress = false;
     }

    public void SendMail()
     {
         MailMessage msg = new MailMessage();
         msg.From = new MailAddress("abc@gmail.com");
         msg.To.Add("asdf@rediffmail.com");
         msg.Body = "Testing the automatic mail";
         msg.IsBodyHtml = true;
         msg.Subject = "Movie Data";
         SmtpClient smt = new SmtpClient("smtp.gmail.com");
         smt.Port = 587;
         smt.Credentials = new NetworkCredential("abc@gmail.com", "password");
         smt.EnableSsl = true;
         smt.Send(msg);
         string script = "<script>alert('Mail Sent Successfully');self.close();</script>";
         this.ClientScript.RegisterClientScriptBlock(this.GetType(), "sendMail", script);
     }
     public void bw_DoWork(object sender, DoWorkEventArgs e)
     {
         SendMail();
     }
     protected void Button1_Click(object sender, EventArgs e)
     {

        DateTime current_time = DateTime.Now;
         current_time = current_time.AddSeconds(10);
         Thread.Sleep(10000);
         if (current_time == DateTime.Now)
         {
             bw.RunWorkerAsync();
         }
     }
 }