// move an item and return true if it really moved.
// Also translate the indices to "leaf" coordinates
internal bool Move(object item, IList list, ref int oldIndex, ref int newIndex)
{
int oldIndexLocal = -1, newIndexLocal = -1;
int localIndex = 0;
int n = ProtectedItems.Count;
// the input is in "full" coordinates. Find the corresponding local coordinates
for (int fullIndex = 0; ; ++fullIndex)
{
if (fullIndex == oldIndex)
{
oldIndexLocal = localIndex;
if (newIndexLocal >= 0)
{
break;
}
++localIndex;
}
if (fullIndex == newIndex)
{
newIndexLocal = localIndex;
if (oldIndexLocal >= 0)
{
--newIndexLocal;
break;
}
++fullIndex;
++oldIndex;
}
if (localIndex < n && ItemsControl.EqualsEx(ProtectedItems[localIndex], list[fullIndex]))
{
++localIndex;
}
}
// the move may be a no-op w.r.t. this group
if (oldIndexLocal == newIndexLocal)
{
return(false);
}
// translate to "leaf" coordinates
int low, high, lowLeafIndex, delta = 0;
if (oldIndexLocal < newIndexLocal)
{
low = oldIndexLocal + 1;
high = newIndexLocal + 1;
lowLeafIndex = LeafIndexFromItem(null, oldIndexLocal);
}
else
{
low = newIndexLocal;
high = oldIndexLocal;
lowLeafIndex = LeafIndexFromItem(null, newIndexLocal);
}
for (int i = low; i < high; ++i)
{
CollectionViewGroupInternal subgroup = Items[i] as CollectionViewGroupInternal;
delta += (subgroup == null) ? 1 : subgroup.ItemCount;
}
if (oldIndexLocal < newIndexLocal)
{
oldIndex = lowLeafIndex;
newIndex = oldIndex + delta;
}
else
{
newIndex = lowLeafIndex;
oldIndex = newIndex + delta;
}
// do the actual move
ProtectedItems.Move(oldIndexLocal, newIndexLocal);
return(true);
}