Get email delivery and read receipt by HttpModule

protected void btnSendMail_Click(object sender, EventArgs e)
 {
   // a unique-id to attach with the mail
var messageId = Guid.NewGuid();
   // the server get request from the image and process it
var externalfile= "http://www.yoursite.com//images//MyDemo.aspxf?key=textkey";
   // the image tag with "src" pointing to the external resource
  // passing necessary parameter and unique-id in the query-string.
   var imgTag =
   string.Format(@"
   style=""width: 0px; height: 0px; border:0px;"" />",
   externalfile, messageId);
   System.Net.Mail.MailMessage oMail = new System.Net.Mail.MailMessage("sender@mainhost.com", "receiver@subhost.com")
   oMail.Subject = "Email delivery using HttpModule";
   oMail.Body = "An image is attached with this email, please enable the images on reading the email so we will know you got the email.";
   //append the image tag at the end of the body.
  oMail.Body += imgTag;
  oMail.IsBodyHtml = true;
            SmtpClient sm = new SmtpClient("smtp.gmail.com");
            sm.Port = 587;
            sm.DeliveryMethod = SmtpDeliveryMethod.Network;
            sm.Credentials = new System.Net.NetworkCredential("userid", "password");
            sm.EnableSsl = true;
    }

public class Request1 : IHttpModule { private string pattern = @"/images/(?.*).aspx"; private string logoFile = "~/logo.jpg"; public Request1() { } public void Dispose() { } public void Init(System.Web.HttpApplication Appl) { Appl.BeginRequest += new System.EventHandler(GetImage_BeginRequest); } public void GetImage(object sender, System.EventArgs args) { //cast the sender to a HttpApplication object System.Web.HttpApplication application = (System.Web.HttpApplication)sender; string url = application.Request.Path; //get the url path //create the regex to match for becon images Regex r = new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase); if (r.IsMatch(url)) { MatchCollection mc = r.Matches(url); if ((mc != null) && (mc.Count > 0)) { string key = (mc[0].Groups["key"].Value); GetKey(key); } //now send the image to the client application.Response.ContentType = "image/gif"; application.Response.WriteFile(application.Request.MapPath(logoFile)); //end the resposne application.Response.End(); } } private void GetKey( string key ) { if ((key == null) || (key.Trim().Length == 0)) return; } }

  <system.web>
     <httpModules>
       <add type="LoadImage.Request1,LoadImage" name="LoadImage" />
     </httpModules>
  </system.web>

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