private void frm_subject_master_Load(object sender, EventArgs e)
        {
            exam_code = null;
            group_code = null;
            ob = new class_Application();
           
            s = "select exam_code,exam_name from exam_master;";
            ob.fill_combo_box(comboBox1, s, "exam_name");
            s = "select group_code,group_name from group_master";
            ob.fill_combo_box(comboBox2, s, "group_name");

        }
 private void frm_create_test_Load(object sender, EventArgs e)
 {
     s=null;
     ob=new class_Application();
     s = "select exam_code,exam_name from exam_master;";
     ob.fill_combo_box(comboBox1, s, "exam_name");
  }
        private void frm_subject_master_Load(object sender, EventArgs e)
        {
            exam_code = null;
            ob = new class_Application();
            //---filling the combobox1-->
            s = "select exam_code,exam_name from exam_master;";
            ob.fill_combo_box(comboBox1, s, "exam_name");



        }