protected override void InsertItem(int index, VObject item)
{
if (item.Layer != null)
{
throw ExceptionFactory.ItemBelongsCollection();
}
base.InsertItem(index, item);
}
protected override void InsertItem(int index, Layer item)
{
// Make sure item can not be added into multiple collections
if (item.Canvas != null)
{
throw ExceptionFactory.ItemBelongsCollection();
}
base.InsertItem(index, item);
}
private void CheckIfItemExists(T newItem)
{
var itemBelongsCollection = false;
foreach (var item in Items)
{
if (ReferenceEquals(item, newItem))
{
itemBelongsCollection = true;
break;
}
}
if (itemBelongsCollection)
{
throw ExceptionFactory.ItemBelongsCollection();
}
}
