public bool ChildLinksTo(N2.ContentItem item)
{
if (item == null)
throw new ArgumentNullException("item", "item is null.");
if(!item.IsPage)
throw new InvalidOperationException("item is not a page");
string url = item.GetSafeUrl().ToUri().AbsolutePath;
// Destination URLs are forced to match the absolute path of the Safe URL for
// internally Hyperlink items so there is no need to fetch the destination web page to
// determine its safe url.
return this.MapItems
.Any(mapItem =>
mapItem.DestinationUrl == url
|| mapItem.ChildLinksTo(item));
}