private void DeleteClicked(object sender, EventArgs e) { ExamRepository eRepo = new ExamRepository(); string[] acc2 = this.comboBoxCourseId.Text.Split(' '); if (eRepo.Delete2(acc2[0]) != 0) { MessageBox.Show("One Exam Deleted", "Successful"); this.dataGridViewExam.DataSource = eRepo.GetAllExams2(); } else { MessageBox.Show("Exam For This Course ID Doesn't Exists", "Failed"); } }