private void AddOperation_Click(object sender, RoutedEventArgs e)
 {
     using (var DB = new SkladModel())
     {
         if (CB_Oper.SelectedItem.ToString() == "Покупка")
         {
             MessageBox.Show(DB.AddOperation(SkladTable.OperationStatus.Purchase, TB_Doc.Text, Convert.ToInt32(TB_NumD.Text),
                                             quantityProduct, DP_Date_Of_Completion.SelectedDate,
                                             Convert.ToInt32(CB_Empl.SelectedValue), productId));
             quantityProduct.Clear();
             productId.Clear();
         }
         if (CB_Oper.SelectedItem.ToString() == "Продажа")
         {
             MessageBox.Show(DB.AddOperation(SkladTable.OperationStatus.Sale, TB_Doc.Text, Convert.ToInt32(TB_NumD.Text),
                                             quantityProduct, DP_Date_Of_Completion.SelectedDate,
                                             Convert.ToInt32(CB_Empl.SelectedValue),
                                             productId));
             quantityProduct.Clear();
             productId.Clear();
         }
     }
     UpdateTable();
     UpdateComboBox();
 }