public StudentList GetStudents()
        {
            // Return all the students from dictionary
            StudentList list = new StudentList();

            list.AddRange(students.Values);
            return(list);
        }
        //Search button
        public void SearchButton(object o)
        {
            StudentList.Clear();
            var result = StudentService.SearchStudent(new StudentSearchCriteria
            {
                SearchText = SearchBox,
                ClassName  = SelectedClass
            });

            StudentList.AddRange(result);
        }