在c#中从列表中显示类的数据

Question

I was trying to display data of class from list in C#.

Here is my class definition:

    class Vehicle
    {
        public string brand;
        public string model;
    }

    class Car : Vehicle
    {
        double trunk_capacity;            
        int doors_number;
        int vmax;
    }

Here is my code in which i'm adding car element:

    public static void AddCar(List<object> avaliable_cars)
    {
        int x = 0;

        Console.WriteLine("Adding new car:");
        Console.WriteLine("1 - Car");
        Console.WriteLine("2 - Sport Car");
        Console.WriteLine("3 - Truck");

        x = int.Parse(Console.ReadLine());

        switch (x)
        {
            case 1: 
            {
                Console.WriteLine("Adding new Car.");

                avaliable_cars.Add(new Car());
                Console.WriteLine("Brand");
                string brand_tmp = Console.ReadLine();
                Console.WriteLine("Model");
                string model_tmp = Console.ReadLine();
                avaliable_cars.Add(new Car()
                {
                    brand = brand_tmp,
                    model = model_tmp
                });

            } break;
        }

   }

I don't have idea how can i display data from this list.

I was trying to do this

foreach (object car in avaliable_cars)
{
  Console.WriteLine(car);
}

I doesn't works. Also i want to access one element at one time - for example i want to display brand of first car on the list. How can i do this?

PS Im beginner in C#, so im sorry for any stupid elements in my code.

Answer 1

One clean way of doing this is to override ToString()

class Vehicle
{
    public string brand;
    public string model;
    public override ToString()
    {
        return "Brand: " + brand + ", Model: " + model;
    }
}

class Car : Vehicle
{
    double trunk_capacity;            
    int doors_number;
    int vmax;
    public override ToString()
    {
        return base.ToString() +
           "trunk_capacity: " + trunk_capacity; // etc.
    }
}

Then you can simply use

Console.WriteLine(car);

Answer 2

You need cast the object car to the type Car or Vehicle and then print.

foreach (object car in avaliable_cars)
{
  Console.WriteLine(((Vehicle)car).brand);
}

Answer 3

A nice way would be using generics. You could specialize your method AddCar like this:

static void AddCar<T>(List<T> avaliable_cars) 
       where T : Car ,new()
    {
        int x = 0;

        Console.WriteLine("Adding new car:");
        Console.WriteLine("1 - Car");
        Console.WriteLine("2 - Sport Car");
        Console.WriteLine("3 - Truck");

        x = int.Parse(Console.ReadLine());

        switch (x)
        {
            case 1: 
            {
                Console.WriteLine("Adding new Car.");

                avaliable_cars.Add(new T());
                Console.WriteLine("Brand");
                string brand_tmp = Console.ReadLine();
                Console.WriteLine("Model");
                string model_tmp = Console.ReadLine();
                avaliable_cars.Add(new T()
                {
                    brand = brand_tmp,
                    model = model_tmp
                });

            } break;
        }

   }

And to print your data you can simply use T instead of object:

foreach (T car in avaliable_cars)
{
    Console.WriteLine(car);
}

Hope it helps.

Answer 4

We can simply use String.Join or foreach.

       List<string> numbers = new List<string>
                    { "One", "Two", "Three","Four","Five"};

        Console.WriteLine(String.Join(", ", numbers));


List<string> strings = new List<string> { "a", "b", "c" };

strings.ForEach(Console.WriteLine);