protected void LinkButtonManageShopItemsBodyTrackersInputAddClick(object sender, EventArgs e)
 {
     string shopItem = textBoxManageShopItemsBodyTrackersInputShopItem.Text;
     string soldCount = textBoxManageShopItemsBodyTrackersInputSoldCount.Text;
     if (String.IsNullOrEmpty(shopItem) ||
         String.IsNullOrEmpty(textBoxManageShopItemsBodyTrackersInputDateTime.Text) ||
         String.IsNullOrEmpty(soldCount))
     {
         labelManageShopItemsStatus.Text = "Select shop item first!";
         return;
     }
     Guid shopItemId = new Guid(shopItem);
     Tracker tracker = new Tracker() {ShopItemId = shopItemId, SoldCount = Misc.String2Number(soldCount)};
     DataBase dataBase = new DataBase();
     dataBase.InsertTracker(tracker);
     DataSet dataSet = dataBase.GetTrackers(shopItemId);
     PopulateTrackers(dataSet);
 }