//if selectedProduct has a recipe - display it in the recipe listbox
 private void DisplayRecipeIfExists(ProductModel selectedProduct)
 {
     if (selectedProduct.RecipeId != null)
     {
         RecipesListBox.SelectedItem = RecipeList.Where(r => r.Id == selectedProduct.RecipeId).First();
     }
     else
     {
         RecipesListBox.ClearSelected();
     }
 }