public Feature[] GetFeatures(Envelope envelope)
{
if (_features == null)
{
return(null);
}
if (envelope == null)
{
return(null);
}
Envelope validExtent = _envelope.IntersectWith(envelope);
if (validExtent == null)
{
return(null);
}
List <Feature> retFets = new List <Feature>();
foreach (Feature fet in _features)
{
if (validExtent.Contains(fet.Geometry.Envelope))
{
retFets.Add(fet);
}
else
{
if (fet.Geometry.Envelope.IsInteractived(validExtent))
{
retFets.Add(fet);
fet.IsRepeatedOverGrids = true;
}
}
}
return(retFets.Count > 0 ? retFets.ToArray() : null);
}
private void TryCheckUnloadedGrids(IFeatureLayer layer, Envelope currentExtent)
{
if (layer == null || currentExtent == null)
{
return;
}
IFeatureClass fetclass = layer.Class as IFeatureClass;
//所有网格已经全部在内存，无需读取
if ((fetclass.DataSource as IFeatureDataSource).ReadIsFinished)
{
return;
}
if ((fetclass.DataSource as IFeatureDataSource).GridStateIndicator.GetUnFlagedCount() == 0)
{
TryEndRead(fetclass.DataSource as IGridReader, fetclass.Name);
_finishedLayerCount++;
return;
}
Envelope validExtent = currentExtent.IntersectWith(fetclass.FullEnvelope);
//
if (validExtent == null)
{
return;
}
//将可使区域转换为数据源的坐标类型
ProjectEnvelope(validExtent, fetclass);
//计算未读出的网格编号
_tempGridNos.Clear();
(fetclass.DataSource as IFeatureDataSource).GridStateIndicator.GetDiffGridNos(validExtent, _tempGridNos);
if (_tempGridNos == null || _tempGridNos.Count == 0)
{
return;
}
//往加载网格队列中添加任务
for (int i = 0; i < _tempGridNos.Count; i++)
{
(fetclass.DataSource as IFeatureDataSource).GridStateIndicator.Flaging(_tempGridNos[i]);
_waitingReadingTaskes.Push(new TaskState(fetclass, _tempGridNos[i]));
}
}
