/// <summary>
 /// <see cref="DeleteButton"/>被点击,调用<see cref="ActivityDetailsPage.DeleteActivity"/>
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 private async void DeleteButton_Click(object sender, RoutedEventArgs e)
 {
     if (await(this.ActivityMainFrame.Content as ActivityDetailsPage).DeleteActivity())
     {
         ActivityMainFrame.Navigate(typeof(ActivitySchedulePage));
         FramePageType = typeof(ActivitySchedulePage);
     }
 }
        /// <summary>
        /// <see cref="ConfirmButton"/>被点击,根据<see cref="ActivityMainFrame"/>内容物决定操作类型:
        /// 若是添加操作则调用<see cref="ActivityDetailsPage.ConfirmAdd"/>,
        /// 若是修改操作则调用<see cref="ActivityDetailsPage.ConfirmUpdate"/>。
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private async void ConfirmButton_Click(object sender, RoutedEventArgs e)
        {
            var tag = (sender as Button).Tag as string;

            if ((sender as Button).Tag as string == "Add" || (sender as Button).Tag as string == "Update")
            {
                UploadingProgressRingPanel.Visibility = Visibility.Visible;
                var result = await(this.ActivityMainFrame.Content as ActivityEditingPage).Confirm(tag);
                UploadingProgressRingPanel.Visibility = Visibility.Collapsed;
                if (result)
                {
                    await new ContentDialog()
                    {
                        Title = ResourceLoader.GetString(
                            tag == "Add" ? "AddActivitySuccessDialog_Title" : "UpdateActivitySuccessDialog_Title"),
                        PrimaryButtonText = ResourceLoader.GetString(
                            tag == "Add" ? "AddActivitySuccessDialog_PrimaryButtonText" : "UpdateActivitySuccessDialog_PrimaryButtonText")
                    }.ShowAsync();

                    ActivityMainFrame.Navigate(typeof(ActivitySchedulePage));   // 如果成功则导航至 SchedulePage
                    FramePageType = typeof(ActivitySchedulePage);
                }
                else
                {
                    await new ContentDialog()
                    {
                        Title = ResourceLoader.GetString(
                            tag == "Add" ? "AddActivityFailDialog_Title" : "UpdateActivityFailDialog_Title"),
                        Content = ResourceLoader.GetString(
                            tag == "Add" ? "AddActivityFailDialog_Content" : "UpdateActivityFailDialog_Content"),
                        PrimaryButtonText = ResourceLoader.GetString(
                            tag == "Add" ? "AddActivityFailDialog_PrimaryButtonText" : "UpdateActivityFailDialog_PrimaryButtonText")
                    }.ShowAsync();
                }
            }
        }