//the update method is called when the button edit course is clicked
        //this method will cause a window apears where a existing course can be edited
        private void CreateCourse_Click(object sender, RoutedEventArgs e)
        {
            var dlg = new CourseEditor(databaseController);

            dlg.ShowDialog();
            dlg.Close();
            CoursesGrid.ItemsSource = databaseController.RetrieveAllDbCourses();
        }
        // Open course editor with selected course
        private void Update_Click(object sender, EventArgs e)
        {
            if (CoursesGrid.SelectedIndex.Equals(-1))
            {
                return;
            }
            var dlg = new CourseEditor((Course)CoursesGrid.SelectedItem, databaseController);

            dlg.ShowDialog();
            dlg.Close();
            CoursesGrid.ItemsSource = databaseController.RetrieveAllDbCourses();
        }