private void cmdAddProduct_Click(object sender, RoutedEventArgs e)
 {
     try
     {
         if (cmbSalesmen.SelectedItem != null)
         {
             if (cmbSalesmen.SelectedIndex != 0)
             {
                 _modal = new ITNLineItemModal();
                 _modal.Closed += new EventHandler(modal_Closed);
                 _modal.Title = "Add Product to Issue";
                 //_modal.cmbProduct.IsEnabled = true;
                 ITNLineItemViewModel vmItem = _modal.DataContext as ITNLineItemViewModel;
                 vmItem.ClearAndSetup.Execute(null);
                 vmItem.SalesmanId = _vm.SelectedSaleMan.CostCentre;
                 _modal.ShowDialog();
             }
             else
                 MessageBox.Show("Please Select a valid sales man");
         }
         else
             MessageBox.Show("Please select a sales man");
     }
     catch (Exception ex)
     {
         MessageBox.Show(ex.Message);
     }
 }
 private void hlEdit_Click(object sender, RoutedEventArgs e)
 {
     _modal = new ITNLineItemModal();
     _modal.Closed += new EventHandler(modal_Closed);
     _modal.Title = "Edit Product";
   //  _modal.cmbProduct.IsEnabled = false;
     Hyperlink hl = sender as Hyperlink;
     ITNLineItemViewModel vmItem = _modal.DataContext as ITNLineItemViewModel;
     Guid product = (Guid)hl.Tag;
     var lineItem = _vm.LineItems.First(n => n.ProductId == product);
     vmItem.ClearAndSetup.Execute(null);
     vmItem.LoadForEdit(lineItem.ProductId, lineItem.Qty, _vm.GetProductSerials(lineItem.ProductId));
     _vm.IsEdit = true;
     _modal.ShowDialog();
 }