private void checkExam()
 {
     try
     {
         string     query = "select event from Exam_process where Candidate_ID=@Candidate_ID and Exam_ID=@Exam_ID";
         SqlCommand cmd   = new SqlCommand();
         cmd = new SqlCommand(query, sqlconnect.connect());
         cmd.Parameters.AddWithValue("@Exam_ID", exam_ID);
         cmd.Parameters.AddWithValue("@Candidate_ID", frmCandidateLogin.candidatID);
         SqlDataReader rd = cmd.ExecuteReader();
         DataTable     dt = new DataTable();
         dt.Load(rd);
         if (dt.Rows.Count != 0)
         {
             int Event = Int32.Parse(Convert.ToString(dt.Rows[0]["Event"]));
             if (Event == 1)
             {
                 MessageBox.Show("İmtahan artıq keçirilib!");
                 frmCandidateLogin login = new frmCandidateLogin();
                 login.Show();
                 this.Hide();
             }
         }
         sqlconnect.close();
     }
     catch (Exception)
     {
         MessageBox.Show("Sistemdə xəta baş verdi, təkrar cəhd edin");
     }
 }
 private void getExamID()
 {
     try
     {
         string     query = @"select id, topic_id, test_count,min_point,period from exam
                          where group_id in (select group_id from group_candidate where candidate_id=@candidate_id)
                          and begin_date=@login_date
                          and (@login_time between begin_time and @end_time)";
         SqlCommand cmd   = new SqlCommand();
         cmd = new SqlCommand(query, sqlconnect.connect());
         cmd.Parameters.AddWithValue("@Candidate_ID", frmCandidateLogin.candidatID);
         cmd.Parameters.AddWithValue("@Login_date", DateTime.Now.ToString());
         cmd.Parameters.AddWithValue("@Login_time", DateTime.Now.ToString("hh:mm tt"));
         cmd.Parameters.AddWithValue("@End_time", DateTime.Now.AddMinutes(50).ToString("hh:mm tt"));
         SqlDataReader rd = cmd.ExecuteReader();
         DataTable     dt = new DataTable();
         dt.Load(rd);
         if (dt.Rows.Count != 0)
         {
             exam_ID    = Int32.Parse(Convert.ToString(dt.Rows[0]["ID"]));
             topic_ID   = Int32.Parse(Convert.ToString(dt.Rows[0]["Topic_ID"]));
             test_Count = Int32.Parse(Convert.ToString(dt.Rows[0]["Test_Count"]));
             Min_Point  = Int32.Parse(Convert.ToString(dt.Rows[0]["Min_point"]));
             Period     = dt.Rows[0]["Period"].ToString();
             sqlconnect.close();
             checkExam();
             setExamProcess();
             getExamProcessID();
             getTestIDCount();
             getRandomNumbers(lstTest_ID.Count, test_Count, ref randomArray);
             fillExamTests(ref randomArray);
             createRadioButton();
             getSetExamTests();
             rdbtn[0].Checked  = true;
             timerExam.Enabled = true;
             setTime();
         }
         else
         {
             MessageBox.Show("İmtahan aktiv deyil");
             frmCandidateLogin login = new frmCandidateLogin();
             login.Show();
             this.Hide();
         }
     }
     catch (Exception)
     {
         MessageBox.Show("Sistemdə xəta baş verdi, təkrar cəhd edin");
     }
 }