private void return_btn_Click(object sender, EventArgs e)
        {
            Mail_form m = new Mail_form();

            m.Show();
            this.Hide();
        }
        private void send_btn_Click(object sender, EventArgs e)
        {
            try
            {
                dataBase      dataBase = new dataBase();
                SqlConnection con      = dataBase.connect_to_scheduluz_DB();

                string reciver_username = to_txt.Text.Replace(" ", "");

                string query = "Select id from connection_details Where userName = '******'";

                SqlDataAdapter sda = new SqlDataAdapter(query, con);
                DataTable      dtb = new DataTable();
                sda.Fill(dtb);
                if (dtb.Rows.Count > 0)
                {
                    reciver_id = dtb.Rows[0][0].ToString().Trim();

                    con.Open();
                    SqlCommand cmd = new SqlCommand("INSERT INTO Mail_box (user_id_send,user_id_get,date_and_time,msg_txt,subject) VALUES (@user_id_send,@user_id_get,@date_and_time,@msg_txt,@subject)", con);
                    cmd.Parameters.Add("@user_id_send", log_in_page.userId);
                    cmd.Parameters.Add("@user_id_get", reciver_id);
                    cmd.Parameters.Add("@date_and_time", DateTime.Now);
                    cmd.Parameters.Add("@msg_txt", msg_txt.Text);
                    cmd.Parameters.Add("@subject", subject_txt.Text);
                    cmd.ExecuteNonQuery();
                    MessageBox.Show("Your Message has been sent.");

                    Mail_form n = new Mail_form();
                    n.Show();
                    this.Hide();
                }
                else
                {
                    MessageBox.Show("Wrong student name.");
                }
            }
            catch
            {
                MessageBox.Show("Problem detected. please contact your Scheduluz Guide for more information.");
            }
        }