请教版主一个基本概念

heidong2002

在autodesk c#.net的例题三中

[CommandMethod("test")]
public void createCircle()
{

Circle circle;

BlockTableRecord btr;

BlockTable bt;

Transaction trans;

trans = HostApplicationServices.WorkingDatabase.TransactionManager.StartTransaction();

circle = new Circle(new Point3d(10, 10, 0), Vector3d.ZAxis, 2);
bt = (BlockTable)trans.GetObject(HostApplicationServices.WorkingDatabase.BlockTableId, OpenMode.ForRead);

btr = (BlockTableRecord)trans.GetObject(HostApplicationServices.WorkingDatabase.CurrentSpaceId,OpenMode.ForWrite );

btr.AppendEntity(circle);
trans.AddNewlyCreatedDBObject(circle, true); //and make sure the transaction knows about it!

trans.Commit();

trans.Dispose();

}

把bt = (BlockTable)trans....这句注释掉,程序依然照常执行,那通过这句话来打开模型空间有什么用呢?

雪山飞狐_lzh

没什么用，autodesk的示例代码一直都没什么改进，呵呵