//method used to fill the list of zoos
        private void FillZooList()
        {
            zooList = new List <zoo>();

            //have an animal array that will used for the zoos

            Animal [] animalArray1 = { new Animal("simba", 10, "lion"),
                                       new Animal("dumbo",  2, "elephant"),
                                       new Animal("goldi",  5, "giraffe") };
            Animal[]  animalArray2 = { new Animal("yogi",  10, "bear"),
                                       new Animal("george",  2, "monkey"),
                                       new Animal("otto",    5, "ostrich") };
            Animal[]  animalArray3 = { new Animal("elsa", 10, "calf"),
                                       new Animal("baba",   2, "sheep"),
                                       new Animal("gadya",  5, "goat") };
            zoo       zoo1 = new zoo("ramat gan", "safari", animalArray1);
            zoo       zoo2 = new zoo("Tanachi", "cages", animalArray2);
            zoo       zoo3 = new zoo("Chavayot", "petting", animalArray3);

            zooList.Add(zoo1);
            zooList.Add(zoo2);
            zooList.Add(zoo3);
        }//end of FillZooList
        //method to display the animals in the selected zoo
        //parameter is the name of the zoo you want to display
        private void ShowZoo(string zooName)
        {
            //find the reqested zoo
            bool found = false;

            foreach (var gan in zooList)
            {
                if (gan.ZooName == zooName)
                {
                    found      = true; //you found your zoo
                    currentZoo = gan;  //save the found zoo
                    break;
                }
            }//end foreach
            if (found)
            {
                UpGrid.DataContext       = currentZoo;            // have the data for upper grid come from selected zoo
                LBAnimalList.DataContext = currentZoo.AnimalList; //have the listbox display the animals in the zoo
            }
            else
            {
                throw new KeyNotFoundException();
            }
        }