//
        //list that contain all the cities & their streets
        //
        List<city_details> list_of_cities = new List<city_details>();

        //
        //index for the loop that adding the streets & the cities to the list
        //
        int index = 0;

        private void Form1_Load(object sender, EventArgs e)
        {
            //
            //new xml object
            //
            XmlDocument xml = new XmlDocument();
            xml.Load(@"rechov.xml");

            //
            //
            //
            foreach (XmlNode node in xml.SelectNodes("ROWDATA/ROW"))
            {

                //
                //if the list is empty - add new city and new street, and ncrease the index in one.
                //
                if (list_of_cities.Count == 0)
                {
                    list_of_cities.Add(new city_details(node.SelectSingleNode("city_name").InnerText, node.SelectSingleNode("street_name").InnerText));
                    index++;
                }

                //
                //if its not empty -
                //
                else
                {
                    //
                    //if this city and the previous city they not the same city
                    //
                    if ((node.SelectSingleNode("city_name").InnerText != list_of_cities[index - 1].city))
                    {
                        //
                        // add a new city & a new stret, and increase the index in one
                        //
                        list_of_cities.Add(new city_details(node.SelectSingleNode("city_name").InnerText, node.SelectSingleNode("street_name").InnerText));
                        index++;
                    }
                        //
                        //if they same city
                        //
                    else
                    {
                        //
                        //just add a new street
                        //
                        list_of_cities[index - 1].street.Add(node.SelectSingleNode("street_name").InnerText);
                    }
                }

            }
        }