private void DisplayUpdateForm()
{
Student selectedStu = lstStudents.SelectedItem as Student;
var updateForm = new FrmAddUpdateStudent(selectedStu);
updateForm.ShowDialog();
}
private void BtnAddStudent_Click(object sender, EventArgs e)
{
FrmAddUpdateStudent addStuForm = new FrmAddUpdateStudent();
addStuForm.ShowDialog();
PopulateStudentListBox();
}