public static void AssignmentsMenu() { Console.WriteLine(" 1. All Assignments\n 2. Assignments per Student\n 3. Current student's pending Assignments' submisions for a specific week\n 4. Add an Assignment to a Course\n 5. Add an Assignment to a Student\n 6. Create a new Assignment\n 7. Go back"); bool result = Int32.TryParse(Console.ReadLine(), out int choice); while (!result || (choice < 1 && choice > 7)) { Console.Write("Wrong input! Please select from number 1 to 7\n"); result = Int32.TryParse(Console.ReadLine(), out choice); } Console.Clear(); switch (choice) { case 1: List <Assignment> assignments = aDB.GetAssignments(); ShowLists.ShowList(assignments, "Assignments"); break; case 2: ShowLists.ShowAssignmentsPerStudent(); break; case 3: ShowLists.ShowPendingAssignments(); break; case 4: AssignmentsPerCourseManager.AddAssignmentInCourse(); break; case 5: AssignmentsPerStudentManager.AddAssignmentToStudent(); break; case 6: AssignmentManager.CreateAssignment(); break; } }