public static double CostForRent = 0.1; //to rent a book, a client have to pay 0.1*Book price

        public ItemView()
        {
            _manager = new InterfaceManager(this);
            this.InitializeComponent();

            //initialise books for exemple (once, at the first connection of any user)
            if (InterfaceManager.ConnectNum == 0)
            {
                ItCollec.InitialiseFirstBooks();
            }
            InterfaceManager.ConnectNum++;

            //welcome message
            tBWelcome.Text = string.Format("Welocome {0}, have a great visit...", InterfaceManager.ActualUser.Name);
            _manager.InitialiseListeView(); //Show the item in list manager
            _manager.ShowDependingLevel();  //show StackPanel and button dependind of user level
            NonReturnBooks();               //check if the user didn't returned a book
        }
        public string ActionSelector = null; //Show different type of UI depending the critera selectioned by user
        private void comboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            bTEnter.Visibility = SearchBox1.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Visible;

            ComboBoxItem temp = e.AddedItems[0] as ComboBoxItem;

            if (temp == null)
            {
                return;
            }
            switch (temp.Content.ToString())
            {
            case ("All"):
                bTEnter.Visibility = SearchBox1.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;

                _manager.InitialiseListeView();
                break;

            case ("ISBN"):
                bTEnter.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;

                textBlock.Text             = ActionSelector = "ISBN";
                SearchBox1.PlaceholderText = "Enter ISBN...";


                break;

            case ("Name"):
                bTEnter.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;

                textBlock.Text             = ActionSelector = "Name";
                SearchBox1.PlaceholderText = "Enter Name...";

                break;

            case ("Price"):
                bTEnter.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;

                textBlock.Text             = ActionSelector = "Price";
                SearchBox1.PlaceholderText = "Enter minimum price...";
                SearchBox2.PlaceholderText = "Enter maximum price...";
                break;

            case ("Date"):
                SearchBox1.Visibility = SearchBox2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;

                textBlock.Text = ActionSelector = "Date";
                break;

            case ("Categorie"):
                bTEnter.Visibility = SearchBox1.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = bTEnter.Visibility = Visibility.Collapsed;

                string[] categorieString = Enum.GetNames(typeof(Categorie));
                for (int i = 0; i < categorieString.Length; i++)
                {
                    listViewCategorie.Items.Add(categorieString[i]);
                }

                break;

            case ("Best Promo"):
                bTEnter.Visibility = SearchBox1.Visibility = SearchBox2.Visibility = DateSelect1.Visibility = DateSelect2.Visibility = listViewCategorie.Visibility = Visibility.Collapsed;
                _manager.InitialiseListeView(_discountComp);
                textBlock.Text = ActionSelector = "Best Promo";
                break;

            default: return;
            }
        }