private void buttonAddCourse_Click(object sender, EventArgs e) { string courseName = textBoxCourseName.Text; string teacherselected = this.comboBox1.GetItemText(this.comboBox1.SelectedItem); int teacherid = 0; int groupid = 0; int courseid = 0; List <Teacher> teacherlist = duombaze.GetTeacher(); foreach (Teacher teacher in teacherlist) { if (teacherselected == teacher.Name + " " + teacher.Surname) { teacherid = teacher.Id; } } duombaze.AddNewCourse(courseName, teacherid); string groupselected = this.comboBox2.GetItemText(this.comboBox2.SelectedItem); List <Group> grouplist = duombaze.GetGroup(); foreach (Group group in grouplist) { if (groupselected == group.GroupName) { groupid = group.Id; } } List <Course> courselist = duombaze.GetCourse(); foreach (Course course in courselist) { if (courseName == course.Name) { courseid = course.Id; } } duombaze.AddNewLesson(teacherid, groupid, courseid); this.Close(); }