private void UpdatePage(int page, IList <T> results, uint stateWhenRequested)
{
if (stateWhenRequested != State)
{
// this request may contain out-of-date data, so ignore it
return;
}
bool stillRelevant = _requestedPages.Remove(page);
if (!stillRelevant)
{
return;
}
_fetchedPages.Add(page);
var startIndex = page * _pageSize;
for (int i = 0; i < results.Count; i++)
{
var index = startIndex + i;
var virtualItem = _virtualItems[index] ?? (_virtualItems[index] = new VirtualItem <T>(this, index));
if (virtualItem.Item == null || results[i] == null || !_equalityComparer.Equals(virtualItem.Item, results[i]))
{
virtualItem.SupplyValue(results[i]);
}
}
if (results.Count > 0)
{
OnItemsRealized(new ItemsRealizedEventArgs(startIndex, results.Count));
}
}
public VirtualItem <T> this[int index]
{
get
{
RealizeItemRequested(index);
return(_virtualItems[index] ?? (_virtualItems[index] = new VirtualItem <T>(this, index)));
}
set { throw new NotImplementedException(); }
}
public VirtualItem <T> this[int index]
{
get
{
if (index >= Count)
{
throw new ArgumentOutOfRangeException("index");
}
RealizeItemRequested(index);
return(_virtualItems[index] ?? (_virtualItems[index] = new VirtualItem <T>(this, index)));
}
set { throw new NotImplementedException(); }
}
public void Insert(int index, VirtualItem <T> item)
{
throw new NotImplementedException();
}
public bool Remove(VirtualItem <T> item)
{
throw new NotImplementedException();
}
public void Add(VirtualItem <T> item)
{
throw new NotImplementedException();
}
public bool Contains(VirtualItem <T> item)
{
return(item.Parent == this);
}
public int IndexOf(VirtualItem <T> item)
{
return(item.Index);
}
