app级全局数据的临时存储

MyApp.Utilities.SessionState

例子

// Save the session state
            var sessionState = MyApp.Utilities.SessionState[this._pageTitle];
            if (!sessionState) {
                sessionState = { focusedItem: null, scrollPosition: 0 };
                MyApp.Utilities.SessionState[this._pageTitle] = sessionState;

            }
            var currentItem = null;
            var scrollPosition = 0;
            try {
                // Querying the currentItem can throw if listView is loading items from a new dataSource
                currentItem = this._allItemsListView.currentItem;
                scrollPosition = this._allItemsListView.scrollPosition;
            } catch (e) {
                // Do nothing
                // Just save the default values
            }

            sessionState.focusedItem = currentItem;
            sessionState.scrollPosition = scrollPosition;