private void button_GradeCourse_Click(object sender, EventArgs e)
{
this.Hide();
FormExamDepartment_ShowCourse showCourse = new FormExamDepartment_ShowCourse(courseID);
showCourse.Show();
}
private void button_OK_Click(object sender, EventArgs e)
{
FormExamDepartment_ShowCourse show_course = new FormExamDepartment_ShowCourse(Convert.ToInt32(textBox_courseID.Text));
this.Hide();
show_course.Show();
}