XmlDocument doc = new XmlDocument();
            doc.Load("students.xml");
            foreach (XmlNode node in doc.SelectNodes("/students/student"))
            {
                string xml_studentnumber = node.SelectSingleNode("student_number").InnerText;
                string xml_password = node.SelectSingleNode("password").InnerText;

                if (xml_studentnumber == username && xml_password == password)
                {
                    found = 1;
                    // hide fail elements
                    fail_image.Visible = false;
                    fail_label.Visible = false;
                    StoredData.studentnumber = username;
                    main main = new main();
                    main.Show();
                    this.Hide();








                }
                }