Passing and getting data from class

Question

I have 2 forms, form1 and form2 . In form1 I call form2, where I input 2 numbers, one for height and for width of a picturebox. Then I want to pass that data from form2 to form1 , where I create picturebox with said size.
Then I want to store height and width to class and then access that info from form1 .
Here is my code:

Form1

namespace NPA_projekt
{
    public partial class Form1 : Form
    {
        private Form2 f2 = new Form2();

        image img = new image();

        public Form1()
        {
            InitializeComponent();
        }

        private void newToolStripMenuItem_Click(object sender, EventArgs e)
        {
            f2.ShowDialog();
        }

        private void btnTest_Click(object sender, EventArgs e)
        {
            pbMainArea.Width = img.width;
            pbMainArea.Height = img.length;
        }
    }

}    

Form2

    namespace NPA_projekt
{
    public partial class Form2 : Form
    {
        image img = new image();

        public Form2()
        {
            InitializeComponent();
        }

        //reset btn
        private void button1_Click(object sender, EventArgs e)
        {
            nudWidth.Value = 640;
            nudLength.Value = 400;
        }

        //cancel btn
        private void button3_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        //ok btn
        private void btnOK_Click(object sender, EventArgs e)
        {
            img.width = Convert.ToInt32(nudWidth.Value);
            img.length = Convert.ToInt32(nudLength.Value);
            this.Close();
        }
    }
}

Class image

namespace NPA_projekt
{
    class image
    {
        public int width = 0;
        public int length = 0;
    }
}

Values, that are stored in form2 , are set to their original values, when I want to use them in form1 . Could someone please elaborate what's happening. Thank you all!

Answer 1

img is declared twice. Once in Form1 and again in Form2 . When you are setting the width and height of img in Form2 you are setting it for the image instance you declared in Form2 not Form1 . You need to make the img in Form1 visible to Form2 and perform the operation on that.

So, make img in Form1 public:

    public image img {get; set;}
    public Form1()
    {
        InitializeComponent();
        img = new image();
    }

Then you need to access it in Form2 (one way should be the Parent property of the form):

    private void btnOK_Click(object sender, EventArgs e)
    {
        var form1 = (Form1)this.Parent
        form1.img.width = Convert.ToInt32(nudWidth.Value);
        form1.img.length = Convert.ToInt32(nudLength.Value);
        this.Close();
    }

I haven't tested this all out, but the approach is valid. The key to eliminating the confusion is getting rid of the img declaration in Form2 and realizing that you need to get access to Form1 from Form2