Prime numbers from a listbox should appear to a textbox

Question

I want to implement a code that take my inserted values from a listBox and show the as Prime numbers in textbox. Unfortunately, my textbox appear only the index of my prime number.

private void primnr()
    {
        int n = listBox1.Items.Count;

        for(int i=2; i<=n; i++)
        {
            bool prim = true;
            for (int j=2; j <i/2; j++)
            {
                if (i % j == 0)
                {
                    prim = false;
                    break;
                }
            }
            if (prim)
                textBox2.Text = textBox2.Text + "Numerele prime:" +listBox1.Items[i].ToString() + Environment.NewLine ;
        }



    }

Answer 1

Assuming that you have numbers in your Combo items, you should access the item in that index position, in your case “i”

if (prim) textBox2.Text = textBox2.Text + "Numerele prime:" + listBox1.Items[i].ToString() + Environment.NewLine;

Answer 2

when I put this line textBox2.Text = textBox2.Text + "Numerele prime:" + listBox1.Items[i] + Environment.NewLine; it shows this error:System.ArgumentOutOfRangeException: 'InvalidArgument=Value of '2' is not valid for 'index'. Parameter name: index'