C#, problems with objects

Question

Sorry for the rookie question, as I'm just starting out with C#.

I have a class

namespace WindowsFormsApplication1
{
    class people
    {
        public int Cash;
        public string LastName;
        public void GiveCash(int amount) { this.Cash = this.Cash - amount; }
        public void ReceiveCash(int amount) { this.Cash = this.Cash + amount; }

    }
}

and I initialize two object with it.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        people viktor = new people() { Cash = 1000, LastName = "Jushenko" };
        people julia = new people() { Cash = 500, LastName = "Timoshenko" };
    }

but later in the code I can not access any of those objects. For example I i use

    private void button1_Click(object sender, EventArgs e)
    { viktor.cash = 200; }

it says something like "The name 'victor' does not exist in this context..." what am I doing wrong?

Thanks!

Answer 1

You are declaring local variables in the Form1 constructor. You cannot access them after going out of scope. You should declare them as fields in the class, like this:

public partial class Form1 : Form
{
    private people viktor;
    private people julia;
    public Form1()
    {
        InitializeComponent();
        viktor = new people() { Cash = 1000, LastName = "Jushenko" };
        julia = new people() { Cash = 500, LastName = "Timoshenko" };
    }

The fields viktor and julia are now part of your class, and you can access them from your methods inside the class.

Answer 2

The scope of your victor variable is local to the Form1 constructor and can't be accessed outside of it.

You need to promote it to be a field if you want to access it in the event handler:

private people viktor;

public Form1()
{
    InitializeComponent();
    viktor = new people() { Cash = 1000, LastName = "Jushenko" };
    people julia = new people() { Cash = 500, LastName = "Timoshenko" };
}

private void button1_Click(object sender, EventArgs e)
{ 
  viktor.cash = 200;
  // Note: the "julia" variable is not in scope here.
}

Answer 3

There are different scopes that you need to be aware of. The reason why you cannot access your variables is because they are in a scope which you don't got access to.

One solution would be to move the variables out of their current scope:

public partial class Form1 : Form
{
    private people victor = null;
    private people julia = null;
    public Form1()
    {
        InitializeComponent();
        this.viktor = new people() { Cash = 1000, LastName = "Jushenko" };
        this.julia = new people() { Cash = 500, LastName = "Timoshenko" };
    }
....