//--- Display instructor coursrs in list
private void listBox11_SelectedIndexChanged(object sender, EventArgs e)
{
Courses.Items.Clear();
Online_Exame ent = new Online_Exame();
//--get instractor from combo box
string insName = Instructors.SelectedItem.ToString();
var insId = (int)(ent.Get_insid_by_inname(insName)).First();
label7.Text = "of" + " " + insName;
//--get courses of same instructor
var items = ent.get_instructor_course(insId);
foreach (var i in items)
{
Courses.Items.Add(i);
}
}