How do I get the index of a listboxitem in a WPF listbox instance?

Question

The listbox is databound, binding to a collection of XML nodes through xmldataprovider.

Answer 1

I had a similar question which was answered here

Basically you set the ListBox's AlternationCount to something really high, and bind to the AlternationIndex on each item

<ListBox AlternationCount="100">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding RelativeSource={RelativeSource Mode=TemplatedParent},
                                      Path=(ItemsControl.AlternationIndex)}" />
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

Answer 2

You can get the index of the ListBoxItem from the ItemContainerGenerator:

ItemContainerGenerator.IndexFromContainer(my_listBoxItem);

Answer 3

The property SelectedIndex would work. It all depends on how you're doing your binding

You probably want to bind the SelectedIndex dependency property to some property of the object connected to it's datacontext e.g.

<ListBox SelectedIndex="{Binding MySelectedIndex}" ItemsSource="{Binding MyItems}"/>

but you could obviously do this

<ListBox SelectedIndex="{Binding MySelectedIndex}">
  <ListBoxItem>1</ListBoxItem>
  <ListBoxItem>2</ListBoxItem>
  <ListBoxItem>3</ListBoxItem>
  <ListBoxItem>4</ListBoxItem>
</ListBox>