/// <summary>
/// Updates the selection for an item based on user interaction.
/// </summary>
/// <param name="index">The index of the item.</param>
/// <param name="select">Whether the item should be selected or unselected.</param>
/// <param name="rangeModifier">Whether the range modifier is enabled (i.e. shift key).</param>
/// <param name="toggleModifier">Whether the toggle modifier is enabled (i.e. ctrl key).</param>
protected void UpdateSelection(
int index,
bool select = true,
bool rangeModifier = false,
bool toggleModifier = false)
{
if (index != -1)
{
if (select)
{
var mode = SelectionMode;
var toggle = toggleModifier || (mode & SelectionMode.Toggle) != 0;
var multi = (mode & SelectionMode.Multiple) != 0;
var range = multi && SelectedIndex != -1 && rangeModifier;
if (!toggle && !range)
{
SelectedIndex = index;
}
else if (multi && range)
{
SynchronizeItems(
SelectedItems,
GetRange(Items, SelectedIndex, index));
}
else
{
var item = ElementAt(Items, index);
var i = SelectedItems.IndexOf(item);
if (i != -1 && (!AlwaysSelected || SelectedItems.Count > 1))
{
SelectedItems.Remove(item);
}
else
{
if (multi)
{
SelectedItems.Add(item);
}
else
{
SelectedIndex = index;
}
}
}
if (Presenter?.Panel != null)
{
var container = ItemContainerGenerator.ContainerFromIndex(index);
KeyboardNavigation.SetTabOnceActiveElement(
(InputElement)Presenter.Panel,
container);
}
}
else
{
LostSelection();
}
}
}
int IList <Security> .IndexOf(Security item)
{
return(SelectedItems.IndexOf(GetItem(item)));
}