static void AddEmployee()
        {
            string ginNumber       = InputHandler.GetGinNumber();
            string name            = InputHandler.GetName();
            string temperature     = InputHandler.GetTemperature();
            bool   symptom         = InputHandler.GetSymptom();
            bool   hubeiExperience = InputHandler.GetHubeiExperience();

            healthDataHolder.AddEmployee(ginNumber, name, temperature, symptom, hubeiExperience);
            Console.WriteLine("\nYou have finished filling today's investigation.");
            DataPrinter.PrintHeader();
            DataPrinter.PrintAnEmployee(ginNumber, name, temperature, symptom.ToString(), hubeiExperience.ToString());
            Console.WriteLine("Press any key to continue");
            Console.ReadKey();
            Console.Clear();
        }
 public static void LoadDataFromFile()
 {
     Program.healthDataHolder = new HealthDataHolder();
     if (!File.Exists(@"D:\temp\NewHealthFormApplication.csv"))
     {
         Console.WriteLine("The file is not existed.");
         Console.WriteLine("Press any key to continue");
         Console.ReadKey();
         Console.Clear();
     }
     else
     {
         foreach (string line in File.ReadLines(@"D:\temp\NewHealthFormApplication.csv"))
         {
             if (line == "")
             {
                 Console.WriteLine("The file is empty.");
                 Console.WriteLine("Press any key to continue");
                 Console.ReadKey();
                 Console.Clear();
                 return;
             }
             else
             {
                 string[] employeeData    = line.Split(',');
                 string   ginNumber       = employeeData[0];
                 string   name            = employeeData[1];
                 string   temperature     = employeeData[2];
                 bool     symptom         = employeeData[3] == "Yes";
                 bool     hubeiExperience = employeeData[4] == "Yes";
                 Program.healthDataHolder.AddEmployee(ginNumber, name, temperature, symptom, hubeiExperience);
             }
         }
         DataPrinter.PrintHeader();
         foreach (Employee employee in Program.healthDataHolder.DataHolder.Values)
         {
             DataPrinter.PrintAnEmployee(employee.GinNumber, employee.Name, employee.Temperature, employee.Symptom.ToString(), employee.HubeiExperience.ToString());
         }
         Console.WriteLine("Press any key to continue");
         Console.ReadKey();
         Console.Clear();
     }
 }
        static void EditEmployee()
        {
            Console.WriteLine("Please input the gin number of the employee you would like to edit.");
            string ginNumber = Console.ReadLine();

            if (healthDataHolder.DataHolder.ContainsKey(ginNumber))
            {
                string name            = InputHandler.GetName();
                string temperature     = InputHandler.GetTemperature();
                bool   symptom         = InputHandler.GetSymptom();
                bool   hubeiExperience = InputHandler.GetHubeiExperience();
                healthDataHolder.EditEmployee(healthDataHolder.DataHolder, ginNumber, name, temperature, symptom, hubeiExperience);
                DataPrinter.PrintHeader();
                DataPrinter.PrintAnEmployee(ginNumber, name, temperature, symptom.ToString(), hubeiExperience.ToString());
            }
            else
            {
                Console.WriteLine($"\nGin number {ginNumber} is not existed.");
            }
            Console.WriteLine("Press any key to continue");
            Console.ReadKey();
            Console.Clear();
        }
        static void DataPrinterMenu()
        {
            if (healthDataHolder == null || healthDataHolder.DataHolder.Count == 0)
            {
                Console.WriteLine("\nThere is no stored data.");
                Console.WriteLine("Press any key to continue");
                Console.ReadKey();
                Console.Clear();
            }
            else
            {
                while (true)
                {
                    MenuPrinter.PrintFilterMenu();
                    int selection;
                    if (!int.TryParse(Console.ReadLine(), out selection))
                    {
                        Console.WriteLine("\nPlease enter an integer.");
                        Console.WriteLine("Press any key to continue");
                        Console.ReadKey();
                        Console.Clear();
                        continue;
                    }
                    else
                    {
                        switch (selection)
                        {
                        case 1:
                            DataPrinter.PrintDataTable();
                            continue;

                        case 2:
                            DataPrinter.FilterByGinNumber();
                            continue;

                        case 3:
                            DataPrinter.FilterByName();
                            continue;

                        case 4:
                            DataPrinter.FilterByHavingFever();
                            continue;

                        case 5:
                            DataPrinter.FilterByHavingNoFever();
                            continue;

                        case 6:
                            DataPrinter.FilterByHavingSymptom();
                            continue;

                        case 7:
                            DataPrinter.FilterByHavingNoSymptom();
                            continue;

                        case 8:
                            DataPrinter.FilterByHavingHubeiExperience();
                            continue;

                        case 9:
                            DataPrinter.FilterByHavingNoHubeiExperience();
                            continue;

                        case 0:
                            return;

                        default:
                            Console.WriteLine("\nPlease enter valid selection.");
                            Console.WriteLine("Press any key to continue");
                            Console.ReadKey();
                            Console.Clear();
                            continue;
                        }
                    }
                }
            }
        }