bool fl = false;
             sr = new StreamReader("produkt.txt");
             while (!sr.EndOfStream)
             {
                 string line = sr.ReadLine();
                 linePro = line.Split(';');

                // MessageBox.Show("vtri 1: " + linePro[3]);
                 string name=linePro[1];
               //  MessageBox.Show("name: " + linePro[1]);
                 int n=listBox2.Items.Count;

                 for (int i = 0; i < n;i++ )
                 {
                    // MessageBox.Show("hej");
                     if (listBox2.Items[i].ToString().Equals(name))
                     {
                        // MessageBox.Show("hej inne");
                         int antal = Int32.Parse(linePro[3]);
                         updateAntal = antal - 1;
                         MessageBox.Show("vtri 1: " + updateAntal);
                         fl = true;

                     }
                 }
             }
             sr.Close();
            if(fl==true)
            {
                sw = new StreamWriter("produkt.txt", true);
                int n2 = listBox1.Items.Count;
                for (int i = 0; i < n2; i++)
                {

                    sw.WriteLine(linePro[0] + ";" + linePro[1] + ";" + linePro[2] + ";" + updateAntal);

                }
                sw.Close();
            }