Question

I have this subtle program regarding the behavior of listbox. My listbox is binded with an observable list in the viewmodel. There are 2 ways in addding an item in the listbox. First is ADD a single item then that item would be selected directly. This works fine.

The second way was LOAD which by its name will be adding more than 1 item in the lisbox. Now the problem is when loading items more than the listbox can accomodate in the view, those items that are not in view (items at the bottom thus need to be scrolled in order for it to be viewed) was not automatically selected…

Only the items that are by default viewed are the ones selected:

private void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
{

  if (listBoxAddresses.ItemContainerGenerator.Status != GeneratorStatus.ContainersGenerated) return;

  for (int i = 0; i < TestSetting.DeviceSettings.Count; i++)
  {
    ListBoxItem myListBoxItem = (ListBoxItem)(listBoxAddresses.ItemContainerGenerator.ContainerFromItem(TestSetting.DeviceSettings[i]));

    if (myListBoxItem != null)
    {
      myListBoxItem.IsSelected = true;
    }
  }
  listBoxAddresses.ItemContainerGenerator.StatusChanged -= ItemContainerGenerator_StatusChanged;
}

I wonder if this is just a natural behavior for listbox.

Answer 1

I just realize this now…setting my listbox to :

VirtualizingStackPanel.IsVirtualizing="False"

did all the trick. Thanks to Dr.WPF for the idea. Though there are consequences for turning off virtualization (performance) but it won’t matter that much.