void OnKeyDown(object sender, KeyRoutedEventArgs e)
{
if (SelectionMode == SelectionMode.Multiple || RootItems.Count == 0)
{
return;
}
TvItem row;
switch (e.Key)
{
case VirtualKey.Down:
row = SelectedRows.LastOrDefault();
if (row == null)
{
OnToggleSelected(RootItems[0]);
}
else
{
using (var ls = RootItems.GetExpandedItems().GetEnumerator())
{
while (ls.MoveNext())
{
if (ls.Current == row)
{
if (ls.MoveNext())
{
OnToggleSelected(ls.Current);
}
else
{
OnToggleSelected(RootItems[0]);
}
break;
}
}
}
}
e.Handled = true;
return;
case VirtualKey.Up:
row = SelectedRows.LastOrDefault();
if (row == null)
{
OnToggleSelected(RootItems[0]);
}
else
{
using (var ls = RootItems.GetExpandedItems().GetEnumerator())
{
if (ls.MoveNext())
{
if (ls.Current == row)
{
SelectedItem = null;
}
else
{
while (true)
{
TvItem lastRow = ls.Current;
if (ls.MoveNext())
{
if (ls.Current == row)
{
OnToggleSelected(lastRow);
break;
}
}
}
}
}
}
}
e.Handled = true;
return;
case VirtualKey.Enter:
row = SelectedRows.LastOrDefault();
if (row != null)
{
row.OnClick();
}
return;
default:
return;
}
}