Engine中如何实现两个矢量图层间的空间查询？

【解决办法】：
Engine中提供了IQueryByLayer接口可以实现两个图层间的空间查询，有一点需要注意：如果ByLayer中进行了选中，则IQueryByLayer.UseSelectedFeatures可以设为true，如果没有进行选中，那么IQueryByLayer.UseSelectedFeatures设为true或者不设置都查询不到，必须设置为false。

下面测试代码可以查询线完全在面的内部：

IFeatureLayer FromLayer = axMapControl1.get_Layer(0) as IFeatureLayer;//线图层 

IFeatureLayer ByLayer = axMapControl1.get_Layer(1) as IFeatureLayer;//面图层 



IQueryByLayer pQueryByLayer = new QueryByLayerClass(); 

pQueryByLayer.FromLayer = FromLayer; 

pQueryByLayer.ByLayer = ByLayer; 

pQueryByLayer.LayerSelectionMethod = esriLayerSelectionMethod.esriLayerSelectCompletelyWithin; 

pQueryByLayer.UseSelectedFeatures = false; 

ISelectionSet selectionSet = pQueryByLayer.Select(); 

IFeatureSelection pFeatureSelection = (IFeatureSelection)FromLayer; 

pFeatureSelection.SelectionSet = selectionSet; 

axMapControl1.Refresh();