Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

LongListSelector: Item tap?

I am using LongListSelector control on Windows Phone 8 and can't figure out the best way to handle a tap on an item. The few examples I've found rely on the SelectionChanged event. However, this solution is buggy because if I tap an item that opens a new page, hit back, and then tap the same item again, it won't work because this item is already selected, so SelectionChanged is not triggered.

I tried to register to the tap event and use the current selected item as the tapped one, but some times the current selected item is not the one I expect.

I could wrap my ItemTemplate in a button and handle the tap for each item but I need to reskin the button to make it look like a simple list item.

Finally, I don't understand why it is so complicated to achieve such a basic thing. Is there a simple and standard way I missed?

My second wish is to get an effect on the item when it is tapped. Is there any standard way to do it?

like image 333
Tom Esterez Avatar asked Jan 08 '13 12:01

Tom Esterez


2 Answers

You could null your LongListSelector's SelectedItem at the end of each SelectionChanged event. I.e.

<phone:LongListSelector x:Name="LLS" SelectionChanged="LLS_SelectionChanged"> 

And the event handler:

private void LLS_SelectionChanged(object sender, SelectionChangedEventArgs e) {    // If selected item is null, do nothing   if (LLS.SelectedItem == null)     return;    // Navigate to the next page   NavigationService.Navigate(new Uri("/nextpage.xaml", UriKind.Relative));    // Reset selected item to null   LLS.SelectedItem = null; } 

You'll fire the SelectionChanged event twice, but nothing's going to happen the second time round and you should get the behaviour that you're looking for - (i.e Setting SelectedItem to null will trigger a new SelectionChanged event, but this second event gets caught in the if-statement)

As for the second part of your question, you might be better posting a new question.

like image 140
Stevie Avatar answered Sep 30 '22 15:09

Stevie


I done it with the Tap event handling.

I prefer not to use Selected property, but get tapped item this way (and I haven't noticed any bugs):

MyListItemClass item = ((FrameworkElement)e.OriginalSource).DataContext                                                               as MyListItemClass; 

Also, you could get the original item ContentPresenter simple by navigating up through VisualTree from e.OriginalSource. That way:

ContentPresenter itemPresenter = SomeHelperClass                               .FindParent<ContentPresenter>(e.OriginalSource,""); 

Where FindParent is similar to find child in this question: How can I find WPF controls by name or type?

ContentPresenter is that object what you need to manually change the item template if you want to (to set "selected" state for example).

like image 35
gleb.kudr Avatar answered Sep 30 '22 16:09

gleb.kudr