ArcGIS 空间查询

public static bool QueryMessPoint(IActiveView activeView, IFeatureClass featureClass, string whereClause, ISpatialReference spatRef, out IGeometry geometry)
{
            try
            {
                ESRI.ArcGIS.Geodatabase.IQueryFilter queryFilter = new ESRI.ArcGIS.Geodatabase.QueryFilterClass();
                queryFilter.WhereClause = whereClause;

                ESRI.ArcGIS.Geodatabase.IFeatureCursor featureCursor = featureClass.Search(queryFilter, false);

                geometry = Geometry.GeometryOp.ConstructUnion(featureCursor);
                IGeoDataset geodataset = featureClass as IGeoDataset;
                geometry.SpatialReference = geodataset.SpatialReference;
                geometry.Project(spatRef);

                return true;
            }
            catch (System.Exception ex)
            {
                System.Diagnostics.Debug.Write(ex.Message);
                geometry = null;
                return false;
            }
}