//--- 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); } }
//add instructor to choosen course private void button5_Click(object sender, EventArgs e) { try { int crsId = int.Parse(comboBox1.Text); using (Online_Exame ent = new Online_Exame()) { //--get instractor from combo box string insName = comboBox3.Text.ToString(); var insId = (int)(ent.Get_insid_by_inname(insName)).First(); //--add instractor to course ent.Add_Course_instractor(crsId, insId); MessageBox.Show("Added Successfully"); Courses.Items.Clear(); Instructors.Items.Clear(); label7.Text = comboBox1.Text = comboBox3.Text = textBox1.Text = string.Empty; ent.SaveChanges(); } } catch (System.Data.Entity.Core.EntityCommandExecutionException) { MessageBox.Show("This instructor already exist"); } catch (InvalidOperationException) { MessageBox.Show("Please Choose Instructor Name"); } catch (NullReferenceException) { MessageBox.Show("Please Choose Instructor Name"); } catch (System.FormatException) { MessageBox.Show("Please Choose Course ID"); } }