C#列表<T>自动递增

Question

When I create a class that I have created and I create two lists with the new operator, the ID number is in the order of both when I start adding data.

After adding 10 pieces to the list 1, when I start adding 10 to List 2, ID numbers 11, 12, 13 starts to give.

Every list I want is a different way to increase the IDs.

If you can help, good work.

Sample Class

public class Listem
{
    private static int xid;
    public int ID;

    public DateTime Date;

    public byte Week;

    public char Process;
    public string PerName;

    public float Pips;


    public Listem(string PerName, char LongShort, byte Hafta, float Pips)
    {
        xid++;
        this.ID = xid;
        this.PerName = PerName;
        this.Process = LongShort;
        this.Week = Hafta;

        this.Pips = Pips;
    }


    public override string ToString()
    {
        return $"ID : {this.ID}\tPerName : {this.PerName}   Tarih : {String.Format("{0:yyyy-MM-dd}", this.Date)}\tİşlem Yönü :    {this.Process}\tHafta :     {this.Week}\tPips :     {this.Pips}";
    }
}

Main Program

    static void Main(string[] args)
    {
        List<Listem> Liste_1 = new List<Listem>();
        List<Listem> Liste_2 = new List<Listem>();

        for (int i = 0; i < 10; i++)
        {
            Liste_1.Add(new Listem("Ahmet", '2', 2, 9F));
        }
        for (int i = 0; i < 10; i++)
        {
            Liste_2.Add(new Listem("Mehmet", '3', 4, 19F));
        }
        Console.WriteLine("Liste 1  ===============");
        foreach (var item in Liste_1)
        {
            Console.WriteLine(item);
        }
        Console.WriteLine("Liste 2  ===============");
        foreach (var item in Liste_2)
        {
            Console.WriteLine(item);
        }

    }

Result

enter image description here

Answer 1

To use your existing code and get the ID's to reset, you could provide a method to allow the clients to reset the static field xid on the Listem class back to 0 before adding items. This is not a great design, however, because it requires that the client's know they have to call this method before creating a new list.

public class Listem
{
    private static int xid;

    // [Other class code here]

    public static void ResetId()
    {
        xid = 0;
    }
}

If you want to allow the users to control the ID property, then you should probably just make it another public property of the class. Oh, and for that matter, you aren't using properties, you're using public fields, which is also considered a bad design. For public members, always opt for properties.

This is the quickest way to get what you want, though:

// Before populating a new list, always reset the xid field to '0'
Listem.ResetId();

for (int i = 0; i < 10; i++)
{
    Liste_1.Add(new Listem("Ahmet", '2', 2, 9F));
}

// Before populating a new list, always reset the xid field to '0'
Listem.ResetId();

for (int i = 0; i < 10; i++)
{
    Liste_2.Add(new Listem("Mehmet", '3', 4, 19F));
}

---

However a better way to do this would be to make all your public fields properties, including ID , and get rid of the static field:

public class Listem
{
    public int ID { get; set; }
    public DateTime Date { get; set; }
    public byte Week { get; set; }
    public char Process { get; set; }
    public string PerName { get; set; }
    public float Pips { get; set; }

    public Listem(int id, string perName, char longShort, byte hafta, float pips)
    {
        ID = id;
        PerName = perName;
        Process = longShort;
        Week = hafta;
        Pips = pips;
    }

    public override string ToString()
    {
        return $"ID : {ID}\tPerName : {PerName} Tarih : {Date:yyyy-MM-dd}" + 
            $"\tİşlem Yönü : {Process}\tHafta : {Week}\tPips :  {Pips}";
    }
}

Then you can just use the for loop iterator as the ID when creating your lists:

for (int i = 0; i < 10; i++)
{
    Liste_1.Add(new Listem(i, "Ahmet", '2', 2, 9F));
}

for (int i = 0; i < 10; i++)
{
    Liste_2.Add(new Listem(i, "Mehmet", '3', 4, 19F));
}

Then to output the lists, it would look like:

Liste_1.ForEach(Console.WriteLine);
Console.WriteLine(new string('-', Console.WindowWidth));

Liste_2.ForEach(Console.WriteLine);
Console.WriteLine(new string('-', Console.WindowWidth));