private void btnSave_Click(object sender, EventArgs e)
        {
            GroupModel objStudent = new GroupModel();

            if (txtGroupNO.Text.ToString() != "")
            {
                objStudent.GroupNo = int.Parse(txtGroupNO.Text.ToString());
            }
            else
            {
                objStudent.GroupNo = 0;
            }

            objStudent.Year     = ddlYear.SelectedValue.ToString();
            objStudent.Semester = ddlSem.SelectedValue.ToString();
            objStudent.Program  = ddlProgram.SelectedValue.ToString();

            objStudent.GrouID = objStudent.Year + "." + objStudent.Semester + "." + objStudent.Program + "." + objStudent.GroupNo.ToString();

            objCore.insertGroup(objStudent);

            //reset feilds
            txtGroupNO.Text = "";

            loadData();
        }