private void btnDeleteStudent_click(object sender, EventArgs e) { ClassRoom classRoom = _processManagement.getClassRoom(_tbxEditClassID.Text); string idStudent = this._tbxEditIdSV.Text; bool isDelete = classRoom.deleteStudent(idStudent); if (isDelete) { MessageBox.Show("Deleted successfully"); this.dataGridViewStudents.Rows.Clear(); this.dataGridViewStudents.Refresh(); drawDataGridView(classRoom, 0); } else { MessageBox.Show("Deleted fail, try again"); } }