public void mainMenu()
        {
            while (run)
            {
                StandardData = bl.GetAllStandards();
                StudentData  = bl.GetAllStudents();

                DisplayMenu();
                InputChoice();

                Console.WriteLine("Selected: " + choice + "\n");

                switch (Convert.ToInt32(choice))
                {
                    #region Standard Switch
                case 1:     // Add
                    AddStandard();
                    break;

                case 2:     // Update
                    UpdateStandard();
                    break;

                case 3:     // Remove
                    RemoveStandard();
                    break;

                case 4:     // Search by ID
                    SearchStandardID();
                    break;

                case 5:     // Search by name
                    SearchStandardName();
                    break;

                case 6:     // Display all standards
                    GetStandards();
                    break;

                case 7:     // Display standard & all students
                    GetStandardAndStudents();
                    break;
                    #endregion

                    #region Student Switch
                case 8:     // Add
                    AddStudent();
                    break;

                case 9:     // Update
                    UpdateStudent();
                    break;

                case 10:     // Remove
                    RemoveStudent();
                    break;

                case 11:     // Search by ID
                    SearchStudentID();
                    break;

                case 12:     // Search by name
                    SearchStudentName();
                    break;

                case 13:     // Display all students
                    GetStudents();
                    break;

                case 0:     // end
                    Console.WriteLine("Press any key to exit...");
                    Console.ReadKey();
                    run = false;
                    break;

                default:
                    Console.WriteLine("Switch statement error...");
                    break;
                    #endregion
                }
            }
        }