wpf - Setting focus on a ListBox item breaks keyboard navigation

Question

After selecting ListBox item programmatically it is needed to press downup key two times to move the selection. Any suggestions?

View:

<ListBox Name="lbActions" Canvas.Left="10" Canvas.Top="10"
               Width="260" Height="180">
        <ListBoxItem Name="Open" IsSelected="true" Content="Open"></ListBoxItem>
        <ListBoxItem Name="Enter" Content="Enter"></ListBoxItem>
        <ListBoxItem Name="Print" Content="Print"></ListBoxItem>
</ListBox>

Code:

public View()
{
   lbActions.Focus();
   lbActions.SelectedIndex = 0; //not helps
   ((ListBoxItem) lbActions.SelectedItem).Focus(); //not helps either
}

Answer 1

Don't set the focus to the ListBox... set the focus to the selected ListBoxItem. This will solve the "two keyboard strokes required" problem:

if (lbActions.SelectedItem != null)
    ((ListBoxItem)lbActions.SelectedItem).Focus();
else
    lbActions.Focus();

If your ListBox contains something else than ListBoxItems, you can use lbActions.ItemContainerGenerator.ContainerFromIndex(lbActions.SelectedIndex) to get the automatically generated ListBoxItem.

---

If you want this to happen during window initialization, you need to put the code in the Loaded event rather than into the constructor. Example (XAML):

<Window ... Loaded="Window_Loaded">
    ...
</Window>

Code (based on the example in your question):

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        lbActions.Focus();
        lbActions.SelectedIndex = 0;
        ((ListBoxItem)lbActions.SelectedItem).Focus();
    }