private void EditClientButtonClick(object sender, RoutedEventArgs e)
 {
     var client = ClientsDataGrid.SelectedItem as Client;
     if (client != null)
     {
         var cew = new ClientEditWindow(uof.Clients, client.Id);
         cew.ShowDialog();
         UpdateControl();
     }
 }
 private void AddClientButtonClick(object sender, RoutedEventArgs e)
 {
     ClientEditWindow cew = new ClientEditWindow(uof.Clients, -1, true);
     cew.ShowDialog();
     UpdateControl();
 }