C# Instances share same values

programming student here, quite new to what i am about to ask but i'm sure you people will know. I have to make a game where several pictureboxes are created using an array. I also have to make a class that has a health variable of 5. When you click on one of the pictureboxes, its health has to go down by 1. I am as far as this, but the problem is that the health variable is shared by all pictureboxes, where in reality I want every picturebox to have it's own health.

This is my code:

public partial class Form1 : Form
{

    Invader monster; // Invader is the name of the class
    Random rand = new Random();
    PictureBox[] pb = new PictureBox[5];

    private void Spawner()
    {
        for (int i = 0; i < 5; i++)
        {
            this.monster = new Invader();
            this.pb[i] = new PictureBox();
            this.pb[i].Name = "pb" + i.ToString();
            this.pb[i].Location = new Point(rand.Next(10, 300), monster.LocY);
            this.pb[i].BackgroundImageLayout = ImageLayout.Stretch;
            this.pb[i].BackgroundImage = Image.FromFile(@"Path");
            this.pb[i].BackColor = Color.Transparent;
            this.pb[i].Size = new System.Drawing.Size(40, 30);
            this.Controls.Add(this.pb[i]);
            this.pb[i].Click += this.Form1_Click;
        }
    }

    private void Form1_Click(object sender, EventArgs e)
    {
        PictureBox currentpicturebox = (PictureBox)sender;

        this.monster.HealthDown();
        if (this.monster.Health == 0)
        {
            currentpicturebox.Dispose();
        }

    }

and my class:

class Invader
{
    // Fields
    private int health;

    // Properties
    public int Health
    {
        get { return this.health; }
    }

    // Constructor
    public Invader()
    {
        this.health = 5;
    }
    // Methods
    public void HealthDown()
    {
            this.health -= 1;
    }

Lets say i click 1 picture box 4 times, and click another one 1 time. With this code the picturebox last clicked on will be disposed. Any ideas on how to fix this?

Your Invader monster is an instance variable of Form1 and in your method Spawner() inside the for loop you are reassigning it again every time: this.monster = new Invader();

Basically when you click on a picturebox (isn't different what) in your Form1_Click method happen that is everytime your last monster istance that get it's health down and not the supposed one.

In order to fix this you can:

• transform monster in an array of Invader object instead of an Invader object, the number of elements must be the same as the number of pictureboxes
• foreach picturebox assign as a Tag the index of the corrispondent Invader on the monster array

Here an example:

public partial class Form1 : Form
{
    // EDIT - Become an array
    Invader[] monster = new Invader[5]; // Invader is the name of the class
    Random rand = new Random();
    PictureBox[] pb = new PictureBox[5];

    private void Spawner()
    {
        for (int i = 0; i < 5; i++)
        {
            this.monster[i] = new Invader(); // EDIT
            this.pb[i] = new PictureBox();
            this.pb[i].Name = "pb" + i.ToString();
            this.pb[i].Location = new Point(rand.Next(10, 300), monster.LocY);
            this.pb[i].BackgroundImageLayout = ImageLayout.Stretch;
            this.pb[i].BackgroundImage = Image.FromFile(@"Path");
            this.pb[i].BackColor = Color.Transparent;
            this.pb[i].Size = new System.Drawing.Size(40, 30);
            this.Controls.Add(this.pb[i]);
            this.pb[i].Click += this.Form1_Click;
            this.pb[i].Tag = i; // EDIT - Added tag assignation
        }
    }

    private void Form1_Click(object sender, EventArgs e)
    {
        PictureBox currentpicturebox = (PictureBox)sender;
        this.monster[(int)currentpicturebox.Tag].HealthDown(); // EDIT
        if (this.monster[(int)currentpicturebox.Tag].Health == 0) //EDIT
        {
            currentpicturebox.Dispose();
        }
    }