/// <summary>
        /// 画面が読み込まれた後に呼ばれます。
        /// </summary>
        /// <param name="sender">sender</param>
        /// <param name="e">e</param>
        private async void ViewLoaded(object sender, RoutedEventArgs e)
        {
            this.viewModel = this.DataContext as NewsManageViewModel;

            this.viewModel.IsBusy = true;
            await this.GetNewsCategoryList();

            await this.GetNewsList();

            this.viewModel.IsBusy = false;
        }
        /// <summary>
        /// ニュース編集ボタンが押されたときに呼ばれます。
        /// </summary>
        /// <param name="sender">sender</param>
        /// <param name="e">e</param>
        private void EditNewsButtonClick(object sender, RoutedEventArgs e)
        {
            var childView      = new NewsManageView();
            var childViewModel = new NewsManageViewModel();

            childViewModel.UserId      = this.viewModel.UserId;
            childViewModel.DisplayName = this.viewModel.DisplayName;
            childViewModel.AccessToken = this.viewModel.AccessToken;
            childView.DataContext      = childViewModel;
            childView.Owner            = this;
            childView.ShowDialog();
        }