Question

I have this Checked List Box, listPlayers. I would like to have it add (or remove) names when asked. These names are in string input, naturally.

Here is the code in question:

namespace TakoBot
{
    static class Program
    {
        public static Form1 MainForm { get; private set; }
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            MainForm = new Form1();
            Application.Run(new Form1());
        }
        public static void OnMessage(object sender, PlayerIOClient.Message m)
        {
            if (m.Type == "add")
            {
                NamesInt[m.GetString(1)] = m.GetInt(0);
                NamesString[m.GetInt(0)] = m.GetString(1);
                Program.MainForm.listPlayers.Add("PlayersName");
            }
        }
    }
}

Upon calling the action Form1.listPlayers.Add("PlayersName");, we get the error:

"'MyProgram.Form1.listPlayers' is inaccessible due to its protection level"

..Okay, my error-handling skills aren’t the best. Like I said, everything is public.

If I’m using entirely wrong actions, don’t hesitate to show me correct ones.

Answer 1

Form1 is a type, not an instance.

In your Program do something like this

static class Program
{
    public static Form1 MainForm { get; private set; }

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);

        MainForm = new Form1();
        Application.Run(MainForm);
    }
}

Now you can reference the form like this (listPlayers must be public)

Program.MainForm.listPlayers.Add("PlayersName");

---

As an alternative, you could expose the player list as a static property in Form1

public partial class Form1 : Form
{
    public static CheckedListBox PlayerList { get; private set; }

    public Form1()
    {
        InitializeComponent();
        PlayerList = listPlayers;
    }

    ...
}

Now you can access it like

Form1.PlayerList.Add("PlayersName");

because it is static, i.e. PlayerList belongs to the type (class) Form1, not to an instance (object) of Form1. This works only if you have only one instance of Form1 open at any time.

---

Given

class MyClass
{
    public static string S;
    public string I;
}

You can do this

MyClass a = new MyClass();
MyClass b = new MyClass();

a.I = "Hello";
MyClass.S = "One";

b.I = "World";
MyClass.S = "Two";

The static variable MyClass.S can have only one value at a given time. It will be "Two" at the end of this code.

The instance variable I can have a different value in each instance (a, b). At the end of this code a.I will be "Hello" and b.I will be "World".