protected void submitBtn_Click(object sender, EventArgs e)
        {
            // Variables declaration
            double totalMark = 0.0;
            Guid   assessID  = Guid.Empty;
            string studID    = "";


            try
            {
                assessID = Guid.Parse(Page.RouteData.Values["id"].ToString());
                studID   = Page.RouteData.Values["studId"].ToString();
            }
            catch (Exception)
            {
                Response.Redirect("/lecturer/list");
            }

            using (OnlineAssessmentDBEntities db = new OnlineAssessmentDBEntities())
            {
                Student_Assessment studAssess = db.Student_Assessment.Where(sa => sa.aspnet_Users.LoweredUserName.Equals(studID.ToLower()) && sa.assessmentId == assessID).FirstOrDefault();

                if (studAssess is null)
                {
                    Response.Redirect("/lecturer/list");
                }

                List <Question> questions = studAssess.Assessment.Question.ToList();

                // Iterate and display questions
                for (int i = 0; i < questions.Count; i++)
                {
                    TextBox markTxtBox = questionPlaceHolder.FindControl($"writtenAns_qm{i + 1}") as TextBox;
                    totalMark += Convert.ToDouble(markTxtBox.Text);
                }

                // Calculate final mark
                totalMark /= Convert.ToDouble(questions.Count);

                studAssess.score = Convert.ToInt16(totalMark);
                db.SaveChanges();

                // Display label
                totalMarkLbl.Text        = $"{Convert.ToInt16(totalMark).ToString()} ({studAssess.getGrade()})";
                alertPlaceholder.Visible = true;

                // Send an email of the score to student
                sendEmailToStudent(studAssess);
            }
        }
        // Method to send email to student
        private void sendEmailToStudent(Student_Assessment studAssess)
        {
            // Create an SMTP client server object to connect to hotmail server
            SmtpClient smtpServer = new SmtpClient("smtp.live.com");

            smtpServer.Port = 587;
            smtpServer.UseDefaultCredentials = false;
            smtpServer.Credentials           = new System.Net.NetworkCredential("*****@*****.**", "%TGB6yhn^YHN5tgb");
            smtpServer.EnableSsl             = true;

            // Create new MailMessage object to send an email
            MailMessage mailMessage = new MailMessage();

            mailMessage.IsBodyHtml = true;
            mailMessage.Subject    = $"Score for assessment {studAssess.Assessment.assessName}";
            mailMessage.From       = new MailAddress("*****@*****.**");
            mailMessage.To.Add(studAssess.aspnet_Users.aspnet_Membership.Email);
            mailMessage.Body = $"Your assessment for \"{studAssess.Assessment.Subject1.subjectName} - {studAssess.Assessment.assessName}\" has just been graded!<br/>Your score is {studAssess.score} ({studAssess.getGrade()}).";

            // Send the email
            smtpServer.Send(mailMessage);
        }