将列表框selectedItems从一个WPF页面发送到另一页面

Question

I am trying to select items from listbox 1 on mainpage, click a button called add and send the items to a new page. But i am dont think my method in doing so is right.

MainPage.xaml.cs

private void btnAdd_Click(object sender, RoutedEventArgs e)
    {

        List<Names> tmp = new List<Names>();

         foreach(var names in lstNames.SelectedItems)
         {
             tmp.Add(names);
         }
         lstNames.ItemsSource = tmp;

        Frame.Navigate(typeof(Page2), tmp);

    }

Page2.xaml.cs

protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        base.OnNavigatedTo(e);

        var tmp = (Names)e.Parameter;

        lstNames2.ItemsSource = tmp;
    }
}

Any guidance is appreciated on how I do this.

Answer 1

The object you pass as the second parameter ends up in the ExtraData property of the NavigationEventArgs.

private void btnAdd_Click(object sender, RoutedEventArgs e)
{
     var tmp = lstNames.SelectedItems.ToList();
     Frame.Navigate(typeof(Page2), tmp);
}

I'm using Linq for the ToList() there.

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    base.OnNavigatedTo(e);
    lstNames2.ItemsSource = e.ExtraData as List<Name>;
}

I recommend you look at MVVM though. The way I would do this is an approach called viewmodel first. I'd use a contentcontrol rather than a frame and have usercontrols rather than pages in it. I'd use templating to template a viewmodel into a page-equivalent usercontrol.

Passing the list would be into the constructor of the viewmodel I "navigate" to. It's a standard wpf technique you should be able to easily google.