/// <summary>
        /// SplitView中ListItem选中项事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void splitViewListItems_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (null != svModel && svModel.Count > 0)
            {
                var selectItem = svModel[0];

                //如果当前显示“退 出”,则表示已经登录,要清除用户信息
                if (selectItem.SplitViewTitle.Contains("退 出"))
                {
                    localSettings.Values["userIdentity"] = null;

                    MainPageSplitViewItemEntity svItemLoginOrLogOff = new MainPageSplitViewItemEntity();
                    //判断用户是否登录过
                    string userIdentity = localSettings.Values["userIdentity"] as string;

                    //不为空则表示登录过
                    if (!string.IsNullOrEmpty(userIdentity))
                    {
                        svItemLoginOrLogOff.IconFont           = "\ue603";
                        svItemLoginOrLogOff.SplitViewTitle     = "退 出";
                        svItemLoginOrLogOff.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";
                    }
                    else
                    {
                        svItemLoginOrLogOff.IconFont           = "\ue604";
                        svItemLoginOrLogOff.SplitViewTitle     = "登 录";
                        svItemLoginOrLogOff.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";
                    }

                    MainPageSplitViewItemEntity svItemRegister = new MainPageSplitViewItemEntity();
                    svItemRegister.IconFont           = "\ue605";
                    svItemRegister.SplitViewTitle     = "注 册";
                    svItemRegister.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";

                    if (null != svModel)
                    {
                        svModel.Clear();
                    }

                    svModel.Add(svItemLoginOrLogOff);
                    svModel.Add(svItemRegister);

                    splitViewListItems.ItemsSource = svModel;
                }

                else if (splitViewListItems.SelectedIndex == 1)
                {
                    //导航到“注册”页
                    this.Frame.Navigate(typeof(UserRegister));
                }//如果当前显示“登录”,则表示未登录,要转向登录页面
                else if (selectItem.SplitViewTitle.Contains("登 录"))
                {
                    //导航到“登录”页
                    this.Frame.Navigate(typeof(UserLogin));
                }
            }
        }
        /// <summary>
        /// 初始化主页数据的方法
        /// </summary>
        public async void InitMainPageDatas()
        {
            //使用导航缓存
            NavigationCacheMode = Windows.UI.Xaml.Navigation.NavigationCacheMode.Disabled;

            MainPageSplitViewItemEntity svItemLoginOrLogOff = new MainPageSplitViewItemEntity();

            //判断用户是否登录过
            string userIdentity = localSettings.Values["userIdentity"] as string;

            //不为空则表示登录过
            if (!string.IsNullOrEmpty(userIdentity))
            {
                svItemLoginOrLogOff.IconFont           = "\ue603";
                svItemLoginOrLogOff.SplitViewTitle     = "退 出";
                svItemLoginOrLogOff.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";
            }
            else
            {
                svItemLoginOrLogOff.IconFont           = "\ue604";
                svItemLoginOrLogOff.SplitViewTitle     = "登 录";
                svItemLoginOrLogOff.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";
            }

            MainPageSplitViewItemEntity svItemRegister = new MainPageSplitViewItemEntity();

            svItemRegister.IconFont           = "\ue605";
            svItemRegister.SplitViewTitle     = "注 册";
            svItemRegister.FontFamilyProperty = "ms-appx:///Assets/Resources/iconfont.ttf#iconfont";

            splitViewListItems.ItemsSource = null;

            svModel.Add(svItemLoginOrLogOff);
            svModel.Add(svItemRegister);

            splitViewListItems.ItemsSource = svModel;

            try
            {
                LoadInitData  = true;
                articlesModel = await HTTPRequestHelper <ArticlesEntity> .requestAndResponseCollections(MobileInterfaceFactory.GET_ALL_ARTICLES_INFO, "{\"paramJsonDatas\":" + pageIndex + "}");

                mainPageList.ItemsSource            = articlesModel;
                progressOfInitFirstDatas.Visibility = Visibility.Collapsed;
            }
            catch (HttpRequestException requestEx)
            {
                //初始化失败计数+1
                initDataFailedCount += 1;

                //异常之后再次请求
                InitMainPageDatas();

                //如果请求次数超出2次,说明不是MySQL超时自动关闭连接的问题而是其他问题,弹出消息框
                if (initDataFailedCount > 2)
                {
                    await ContentDialogTemplateUtil.showContentDialog(SystemMessage.DialogCommonTitleMsg + "HttpRequestException", requestEx.Message, true, false, SystemMessage.DialogButtonByOkValueMsg, String.Empty, ContentDialogStyle.NORMAL).ShowAsync();
                }
            }
            catch (Exception ex)
            {
                //异常之后再次请求
                InitMainPageDatas();

                await ContentDialogTemplateUtil.showContentDialog(SystemMessage.DialogCommonTitleMsg + "Exception", ex.Message, true, false, SystemMessage.DialogButtonByOkValueMsg, String.Empty, ContentDialogStyle.NORMAL).ShowAsync();
            }
        }