Get the index of the selected item in longlistselector

Question

I have a long list selector

<phone:LongListSelector x:Name="BTDevices"  SelectionChanged="BTDevices_SelectionChanged_1">
 <phone:LongListSelector.ItemTemplate>
  <DataTemplate>
   <StackPanel>
    <TextBlock Text="{Binding Path=Name}" FontSize="30" />
   </StackPanel>
  </DataTemplate>
 </phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>

The function is defined as:

private void BTDevices_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
//here i want to get the index of the selected item
}

I tried the following line

int a = App.ViewModel.Items.IndexOf(sender as ItemViewModel);

But it always returns -1.

VasileF VasileF · Accepted Answer · 2013-09-26T18:16:15

When the SelectionChanged event occurs, the senderparameter of the event handler represents the object that triggered this event. It is of type Object, but you can cast it to match your specific control type.

In this case, the LongListSelector :

var myItem = ((LongListSelector) sender).SelectedItem as Model;

(Model represents the type of data your control handles).

Afterwards, look for that item in the ItemsSource and retrieve its value :

var myIndex = ((LongListSelector) sender).ItemsSource.IndexOf(myItem);

You have named your control, so instead of (sender as LongListSelector), you could use its name, BTDevices, but the code lines I wrote was intended to show you what's what with the sender object.

Alternatively (and this is a more elegant way), shown by bland, you could use the EventArgs for selection : e.AddedItems[0]

Get the index of the selected item in longlistselector

2 Answers