cad2008用c#二次开发的填充颜色的问题?

Question

cad2008用c#二次开发的填充颜色的问题,下面的代码画一个圆填充颜色没问题,我想画几根线组合的封闭图形(就是几个对象的封闭图),再填充颜色,该怎么写呢?
  Database db = HostApplicationServices.WorkingDatabase;
                Transaction trans = db.TransactionManager.StartTransaction();
                try
                {
                    Circle circle = new Circle(new Point3d(10, 10, 0), Vector3d.ZAxis, 200);
                                       BlockTable bt = (BlockTable)trans.GetObject(db.BlockTableId, OpenMode.ForRead);
                    BlockTableRecord btr = (BlockTableRecord)trans.GetObject(HostApplicationServices.WorkingDatabase.CurrentSpaceId, OpenMode.ForWrite);
                    btr.AppendEntity(circle);
                
                                      trans.AddNewlyCreatedDBObject(circle, true);
                    ObjectIdCollection collection = new ObjectIdCollection();
                    collection.Add(circle.ObjectId);
                   // collection.Add(circle1.ObjectId);                
                    Hatch hatch = new Hatch();                    hatch.Elevation = 0;
                    hatch.HatchStyle = HatchStyle.Normal;
                    hatch.ColorIndex = 10;
                    hatch.PatternAngle = 0;
                    hatch.SetHatchPattern(HatchPatternType.PreDefined, "SOLID"); //设置填充图案 
                   //  hatch.Associative = true;
                    hatch.AppendLoop(HatchLoopTypes.Default, collection); //设置填充边界 //
                    hatch.EvaluateHatch(true);
                    btr.AppendEntity(hatch);
                    trans.AddNewlyCreatedDBObject(hatch, true);
                    trans.Commit();
                }
                catch
                {
                    ed.WriteMessage("Error ");
                }
                finally
                {
                    trans.Dispose();
                }