将用户输入的项目添加到列表并将列表打印到控制台

Question

I'm making a simple console-program. This program is supposed to give the user a console-menu that will give you three choices: To add an employee to a list, remove an employee from the list, and then to exit. I am trying to create a list that will add different users to the list after they have been initialized by user input. After that I want to print the list to console, but the list wont hold on to any input. If anyone has a clue whats wrong, please tell me, Also, I am fairly new to coding. so extensive explanations are greatly appreciated. Thank you!

using Employees;

namespace Inheritance
{
    public class Program
    {
        static void Main(string[] args)
        {
            bool keepRunning = true;
            while (keepRunning)
            {
                List<Employee> EmployeesList = new List<Employee>();

                 void AddToList(Employee employee)
                {
                    EmployeesList.Add(employee);
                }

                Console.WriteLine("TIFFANYS & CO - PRIVATE PROGRAM TM\nPress the number of the action you want to pursue, and press [ENTER].\n1) Add an Employee\n2) Delete an Employee\n3) Exit");
                var menuChoice = Int32.Parse(Console.ReadLine());
                switch (menuChoice)
                {
                    case 0:
                        foreach (Employee item in EmployeesList)                    
                        {                                                    
                            Console.WriteLine(item.firstName + " " + item.lastName + " " + item.salary);

                        }
                        break;
                    case 1:
                        Console.WriteLine("a) Add a Manager\nb) Add an Engineer\nc) Add a Researcher");
                        var menuChoice1 = Console.ReadLine();

                        switch (menuChoice1)
                        {
                            case "a":


                                Console.WriteLine("Please type in the first name of the manager and press [ENTER]:");
                                string managerFirstName = Console.ReadLine();
                                Console.WriteLine("Please type in the last name of the manager and press [ENTER]:");
                                string managerLastName = Console.ReadLine();
                                Console.WriteLine("Please type in the salary of the manager and press [ENTER]:");
                                int managerSalary = Int32.Parse(Console.ReadLine());
                                Console.WriteLine("Please type in how many meetings the manager will attend weekly and press [ENTER]:");
                                int managerMeetings = Int32.Parse(Console.ReadLine());
                                Console.WriteLine("Please type in how many vacation-weeks the manager has annually and press [ENTER]:");
                                int managerVacationWeeks = Int32.Parse(Console.ReadLine());

                                Manager manager = new(managerFirstName, managerLastName, managerSalary, managerMeetings, managerVacationWeeks);
                                EmployeesList.Add(manager);
                                foreach (var employee in EmployeesList)

                                {
                                    Console.WriteLine(employee);
                                }

                                break;

                            case "b":


                                Console.WriteLine("Please type in the first name of the engineer and press [ENTER]:");
                                string engineerFirstName = Console.ReadLine();
                                Console.WriteLine("Please type in the last name of the engineer and press [ENTER]:");
                                string engineerLastName = Console.ReadLine();
                                Console.WriteLine("Please type in the salary of the engineer and press [ENTER]:");
                                int engineerSalary = Int32.Parse(Console.ReadLine());
                                //Console.WriteLine("Is the engineer able to use C#? If yes, type [yes] and press [ENTER]. If no, type [no] and press [ENTER]:");
                                //string cSkill = Console.ReadLine();
                                //if (cSkill == "yes")
                                //{
                                //    engineer.cSharpSkill = true;
                                //}
                                //else
                                //{
                                //    engineer.cSharpSkill = false;
                                //}
                                Console.WriteLine("How many years of experience does the engineer have? Type the number of years and press [ENTER]:");
                                int engineerExperience = Int32.Parse(Console.ReadLine());
                                Console.WriteLine("What kind of engineering is the engineers field? Please write their field and press [ENTER]:");
                                string engineerField = Console.ReadLine();

                                Engineer engineer = new(engineerFirstName, engineerLastName, engineerSalary, engineerExperience, engineerField);

                                EmployeesList.Add(engineer);

                                break;

                            case "c":


                                Console.WriteLine("Please type in the first name of the researcher and press [ENTER]:");
                                string researcherFirstName = Console.ReadLine();
                                Console.WriteLine("Please type in the last name of the researcher and press [ENTER]:");
                                string researcherLastName = Console.ReadLine();
                                Console.WriteLine("Please type in the salary of the researcher and press [ENTER]:");
                                int researcherSalary = Int32.Parse(Console.ReadLine());
                                Console.WriteLine("What university did the researcher get their Doctorate? Please type in the name of the university and press [ENTER]:");
                                string researcherUniversity = Console.ReadLine();
                                Console.WriteLine("What was the thesis statement of the researchers doctorate? Please type in the thesis question and press [ENTER]:");
                                string researcherThesis = Console.ReadLine();
                                Researcher researcher = new(researcherFirstName, researcherLastName, researcherSalary, researcherUniversity, researcherThesis);

                                EmployeesList.Add(researcher);
                                break;
                        }

                        break;

                    case 2:

                        Console.WriteLine("What is the last name of the engineer to be deleted?");
                        string toDeleteLastName = Console.ReadLine();
                        Employee employeeToBeDeleted = EmployeesList.Find(e => e.lastName == toDeleteLastName);
                        if (employeeToBeDeleted != null)
                            EmployeesList.Remove(employeeToBeDeleted);
                        else
                            Console.WriteLine($"Could not find {employeeToBeDeleted}");
                        break;


                    case 3:
                        keepRunning = false;
                        break;
                }
            }
        }
    }
}

Answer 1

There is a library installed via NuGet, Spectre.Console which makes life easier if you understand how to work with simple classes.

Once the Spectre.Console package has been installed you need the following using statement using Spectre.Console; for all classes. In regard to classes I only did three properties for the Employee model, you need to add the remaining properties if interest in this solution. If you get stuck, see full source but for learning try not to use that code.

Start off with a model/class which represents menu items

public class MenuItem
{
    public int Id { get; set; }
    public string Text { get; set; }
    public override string ToString() => Text;

}

Create a class for presenting the menu

public class MenuOperations
{
    public static SelectionPrompt<MenuItem> MainMenu()
    {
        SelectionPrompt<MenuItem> menu = new()
        {
            HighlightStyle = new Style(
                Color.DodgerBlue1, 
                Color.Black, 
                Decoration.None)
        };

        menu.Title("Select an [B]option[/]");
        menu.AddChoices(new List<MenuItem>()
        {
            new MenuItem() {Id = 0, Text = "List employees"},
            new MenuItem() {Id = 1, Text = "Add manager"},
            new MenuItem() {Id = 2, Text = "Add Engineer"},
            new MenuItem() {Id = 3, Text = "Delete"},
            new MenuItem() {Id = -1, Text = "Exit"},
        });

        return menu;
    }
}

Main code in Program.cs. Following this pattern there is a clear cut path to handling various operations and exiting.

class Program
{
    static void Main(string[] args)
    {
        MenuItem menuItem = new MenuItem();

        List<Employee> EmployeesList = new List<Employee>();

        while (menuItem.Id > -1)
        {

            AnsiConsole.Clear();
            menuItem = AnsiConsole.Prompt(MenuOperations.MainMenu());
            switch (menuItem.Id)
            {
                case 0:
                    Operations.List(EmployeesList);
                    break;
                case 1:
                    Console.WriteLine("Add manager");
                    EmployeesList.Add(Operations.AddEmployee());
                    break;
                case 2:
                    Console.WriteLine("Add Engineer");
                    Console.ReadLine();
                    break;
                case 3:
                    Console.WriteLine("Delete");
                    Console.ReadLine();
                    break;
            }
        }
    }
}

To get an idea how to handle adding a new item and listing items in the list the following code shows how.

• First and last name can not be empty else the prompt stays there. You can add a validation message (see the docs)
• Salary must be a double

With the above in mind you have some simple validation.

public class Operations
{

    public static Employee AddEmployee()
    {
        Employee employee = new Employee
        {
            FirstName = GetFirstName(),
            LastName = GetLastName(),
            Salary = GetSalary()
        };

        return employee;
    }

    public static string GetFirstName() =>
        AnsiConsole.Prompt(
            new TextPrompt<string>("[white]First name[/]?")
                .PromptStyle("yellow")
                .ValidationErrorMessage("[red]Please enter your first name[/]"));

    public static string GetLastName() =>
        AnsiConsole.Prompt(
            new TextPrompt<string>("[white]Last name[/]?")
                .PromptStyle("yellow")
                .ValidationErrorMessage("[red]Please enter your last name[/]"));

    public static double GetSalary() =>
        AnsiConsole.Prompt(
            new TextPrompt<double>("[white]Salary[/]?")
                .PromptStyle("yellow")
                .ValidationErrorMessage("[red]Please enter salary (numbers only)[/]"));

    public static void List(List<Employee> list)
    {
        if (list.Count == 0)
        {
            AnsiConsole.MarkupLine("Nothing is list, press [b]ENTER[/] to return to menu");
            Console.ReadLine();
            return;
        }

        var table = new Table()
            .RoundedBorder()
            .AddColumn("[b]First[/]")
            .AddColumn("[b]Last[/]")
            .AddColumn("[b]Salary[/]")
            .Alignment(Justify.Center)
            .BorderColor(Color.LightSlateGrey)
            .Title("[yellow]Employee list[/]");

        foreach (var employee in list)
        {
            table.AddRow(employee.FirstName, employee.LastName, employee.Salary.ToString("C"));
        }

        AnsiConsole.Write(table);
        AnsiConsole.MarkupLine("Press [b]ENTER[/] to return to menu");
        Console.ReadLine();
    }
}

Some screenshots

Answer 2

You have the loop setup this way:

while (keepRunning)
{
    List<Employee> EmployeesList = new List<Employee>();

So every time you loop you delete the list of employees and get a new one. Try swapping the order:

List<Employee> EmployeesList = new List<Employee>();
while (keepRunning)
{

This way you start your program with a fresh employee list and use that same list while your program is running.