private void Btn_unSelectedItem_Click(object sender, RoutedEventArgs e)
        {//unselect item
            try
            {
                itemUnitOffer = dg_selectedItems.SelectedItem as ItemUnitOffer;
                ItemUnit i = new ItemUnit();
                if (itemUnitOffer != null)
                {
                    i = allItemsSource.Where(s => s.itemUnitId == itemUnitOffer.iuId.Value).FirstOrDefault();

                    allItems.Add(i);

                    selectedItems.Remove(itemUnitOffer);

                    dg_allItems.ItemsSource      = allItems;
                    dg_selectedItems.ItemsSource = selectedItems;

                    dg_allItems.Items.Refresh();
                    dg_selectedItems.Items.Refresh();
                }
            }
            catch (Exception ex)
            {
                SectionData.ExceptionMessage(ex, this);
            }
        }
        private void Btn_selectedItem_Click(object sender, RoutedEventArgs e)
        {//select item
            try
            {
                itemUnit = dg_allItems.SelectedItem as ItemUnit;
                if (itemUnit != null)
                {
                    ItemUnitOffer iUO = new ItemUnitOffer();
                    iUO.ioId         = 0;
                    iUO.iuId         = itemUnit.itemUnitId;
                    iUO.offerId      = offerId;
                    iUO.createUserId = MainWindow.userID;
                    iUO.quantity     = 1;
                    iUO.offerName    = offer.name;
                    iUO.unitName     = itemUnit.unitName;
                    iUO.itemName     = itemUnit.itemName;
                    iUO.itemId       = itemUnit.itemId;
                    iUO.unitId       = itemUnit.unitId;

                    allItems.Remove(itemUnit);
                    selectedItems.Add(iUO);

                    dg_allItems.ItemsSource      = allItems;
                    dg_selectedItems.ItemsSource = selectedItems;

                    dg_allItems.Items.Refresh();
                    dg_selectedItems.Items.Refresh();
                }
            }
            catch (Exception ex)
            {
                SectionData.ExceptionMessage(ex, this);
            }
        }