这个section.Settings为什么一直为null{0}

Section section = new Section(points, Vector3d.ZAxis);
section.SetDatabaseDefaults(newDoc.Database);
ms.AppendEntity(section);// 先入库
dstTrans.AddNewlyCreatedDBObject(section, true);
SectionSettings sectionSettings = (SectionSettings)dstTrans.GetObject(section.Settings, OpenMode.ForRead);
string sectionfilename = sectionSettings.DestinationFile(sectionSettings.CurrentSectionType);
newDoc.Editor.WriteMessage(sectionfilename + “\n”);
//sectionSettings.SetSourceObjects(SectionType.Section2d,new ObjectIdCollection() { item.ObjectId });
sectionSettings.SetHiddenLine(SectionType.Section2d, SectionGeometry.BackgroundGeometry,true);

Array pIntFillEnts;       // 返回包含交集边界几何的数组
Array pBackgroundEnts;    // 返回包含交集填充注释几何的数组 
Array pForegroundEnts;    // 返回包含背景几何的数组
Array pFurveTangencyEnts; // 返回包含前景几何的数组
Array pCurveTangencyEnts; // 返回包含曲线切线几何的数组 
section.GenerateSectionGeometry(item, out pIntFillEnts, out pBackgroundEnts,
   out pForegroundEnts, out pFurveTangencyEnts, out pCurveTangencyEnts);