private async void testbutton_Click(object sender, RoutedEventArgs e)
        {
            string s = await RakutenSearchAPI.JAN_Search(Jancode_Box.Text);

            TestBox.AcceptsReturn = true;
            TestBox.Text          = s;
            Candidate_Set(s);
        }
        private async void exec()
        {
            string s = await RakutenSearchAPI.JAN_Search(Jancode_Box.Text);

            TestBox.AcceptsReturn = true;
            TestBox.Text          = s;
            Candidate_Set(s);
        }
        private async void DataGrid_CurrentCellChanged(object sender, EventArgs e)
        {
            DataGrid dg = (DataGrid)sender;

            if (dg.SelectedItem == null)
            {
                return;
            }
            Item item = dg.SelectedItem as Item;

            last_jan = item._janCode;
            try
            {
                string s = await RakutenSearchAPI.JAN_Search(item._janCode);

                Candidate_Set(s);
            }
            catch
            {
                //dg.SelectedItem = null;
            }
        }
        private async void JANCODE_TEXT_KeyDown(object sender, KeyRoutedEventArgs e)
        {
            if (e.Key == Windows.System.VirtualKey.Enter)
            {
                JANCODE_TEXT.IsReadOnly = true;
                if (!CheckFunction.JANCODE_Integrity_Check(JANCODE_TEXT.Text))
                {
                    JANCODE_TEXT.IsReadOnly = false;
                    CheckFunction.Message_Show("Error", "JANコードが正しくありません");
                    JANCODE_TEXT.Text = "";
                    return;
                }

                try
                {
                    string s = await RakutenSearchAPI.JAN_Search(JANCODE_TEXT.Text);

                    Candidate_Set(s);
                }
                catch {
                    JANCODE_TEXT.Text = "";
                    return;
                }
                finally{
                }

                // 謎ポイント
                // 初回、if (Items.First(x => x._janCode == last_jan)._janCode == JANCODE_TEXT.Text)でマッチするレコードがなかった場合例外発生、2回目以降は例外は発生せずelseに飛ぶ
                // 応急措置として同じコードを書いています
                // いろいろおかしい
                try
                {
                    // リスト上に存在する場合
                    if (Items.First(x => x._janCode == JANCODE_TEXT.Text)._janCode == JANCODE_TEXT.Text)
                    {
                        last_jan = JANCODE_TEXT.Text;
                        Items.First(x => x._janCode == JANCODE_TEXT.Text)._num += 1;
                    }
                    else
                    {
                        DatabaseAccess db = new DatabaseAccess();
                        if (db.Search_Item(JANCODE_TEXT.Text))
                        {
                            // DB既登録の場合
                            Item item = db.Get_Item(JANCODE_TEXT.Text);
                            item._num = 1;
                            last_jan  = JANCODE_TEXT.Text;
                            Items.Add(item);
                        }
                        else
                        {
                            // DB未登録の場合
                            Item item = new Item(JANCODE_TEXT.Text, "", 0, 0, 1);
                            last_jan = JANCODE_TEXT.Text;
                            Items.Add(item);
                        }
                    }
                }catch {
                    DatabaseAccess db = new DatabaseAccess();
                    if (db.Search_Item(JANCODE_TEXT.Text))
                    {
                        // DB既登録の場合
                        Item item = db.Get_Item(JANCODE_TEXT.Text);
                        item._num = 1;
                        last_jan  = JANCODE_TEXT.Text;
                        Items.Add(item);
                    }
                    else
                    {
                        // DB未登録の場合
                        Item item = new Item(JANCODE_TEXT.Text, "", 0, 0, 1);
                        last_jan = JANCODE_TEXT.Text;
                        Items.Add(item);
                    }
                }

                //DatabaseAccess db = new DatabaseAccess();
                //db.Insert_Item(item);

                // 処理完了後
                JANCODE_TEXT.Text       = "";
                JANCODE_TEXT.IsReadOnly = false;
            }
        }