C# Arcgis Engine 获得鼠标按下位置的要素

public IFeature GetFeatureOnMouseDown(IPoint point)
        {
            try
            {
                ILayer layer = Common.GetLayerByName(mMap, "地块");
                if (layer == null)
                {
                    MessageBox.Show("请加载地块图层！", "提示");
                    return null;
                }
                //IFeatureLayer fLayer = layer as IFeatureLayer;
                //IFeatureSelection featureSelection = fLayer as IFeatureSelection;
                //featureSelection.Clear();
                //if (featureSelection == null)
                //{
                //    return null;
                //}

                IFeatureLayer featureLayer = layer as IFeatureLayer;
                if (featureLayer == null)
                    return null;
                IFeatureClass featureClass = featureLayer.FeatureClass;
                if (featureClass == null)
                    return null;

                //IPoint point = axMapControl1.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y);
                IGeometry geometry = point as IGeometry;

                double length = ConvertPixelsToMapUnits(axMapControl1.ActiveView, 4);
                ITopologicalOperator pTopo = geometry as ITopologicalOperator;
                IGeometry buffer = pTopo.Buffer(length);
                geometry = buffer.Envelope as IGeometry;

                ISpatialFilter spatialFilter = new SpatialFilterClass();
                spatialFilter.Geometry = geometry;
                switch (featureClass.ShapeType)
                {
                    case esriGeometryType.esriGeometryPoint:
                        spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains;
                        break;
                    case esriGeometryType.esriGeometryPolygon:
                        spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;
                        break;
                    case esriGeometryType.esriGeometryPolyline:
                        spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelCrosses;
                        break;
                }
                spatialFilter.GeometryField = featureClass.ShapeFieldName;
                IQueryFilter filter = spatialFilter as IQueryFilter;

                IFeatureCursor cursor = featureClass.Search(filter, false);
                IFeature pfeature = cursor.NextFeature();
                if (pfeature != null)
                {
                    return pfeature;
                    //featureSelection.Add(pfeature);
                    //pfeature = cursor.NextFeature();
                }
                else
                {
                    return null;
                }
            }
            catch
            {
                return null;
            }
        }

if (pfeature != null)
                {
                    return pfeature;
                    //featureSelection.Add(pfeature);
                    //pfeature = cursor.NextFeature();
                }