长事务实例

static void lzxARX_AcDbDatabaseRefEdit(void)
    {
        AcDbObjectId transId;
        AcDbDatabase* pDb;
        ACHAR* fname;
        struct resbuf* rb;

        //提示让用户选择一个图形文件
        rb = acutNewRb(RTSTR);
        int stat = acedGetFileD(L"Pick a drawing",NULL,L"dwg",0,rb);

        //如果用户选择有误，则提示用户，退出命令
        if ((stat != RTNORM) || (rb == NULL))
        {
            acutPrintf(L"\nYou must pick a drawing file.");
            return;
        }

        //将获得的文件名转换成字符串
        fname = (TCHAR*)acad_malloc(_tcslen(rb->resval.rstring)+1);
        _tcscpy(fname, rb->resval.rstring);
        acutRelRb(rb);

        //打开前面选中的图形文件
        pDb = new AcDbDatabase(Adesk::kFalse);

        //如果打开失败或用户已经打开了些图形
        if (pDb->readDwgFile(fname)!= Acad::eOk)
        {
            acutPrintf(L"\nSorry, that draing is probably already open.");
            return;
        }

        //获得这个图形文件数据库的块表
        AcDbBlockTable* pBlockTable;
        pDb->getSymbolTable(pBlockTable,AcDb::kForRead);

        //获得模型空间块表记录
        AcDbBlockTableRecord* pOtherMsBtr;
        pBlockTable->getAt(ACDB_MODEL_SPACE,pOtherMsBtr,AcDb::kForRead);
        pBlockTable->close();

        //创建一个遍历器
        AcDbBlockTableRecordIterator* pIter;
        pOtherMsBtr->newIterator(pIter);

        //创建一个对象ＩＤ数组
        AcDbObjectIdArray objIdArray;

        //对模型空间块表记录进行遍历
        for (pIter->start();!pIter->done();pIter->step())
        {
            //获得实体
            AcDbEntity* pEntity;
            pIter->getEntity(pEntity,AcDb::kForRead);

            //对实体类型进行断送
            //如果实体是圆，则将实体的对象ＩＤ添加到数组中
            if (pEntity->isKindOf(AcDbCircle::desc()))
            {
                objIdArray.append(pEntity->objectId());
            }

            //关闭实体
            pEntity->close();
        }
        delete pIter;
        pOtherMsBtr->close();

        //如果图形中没有圆对象，则释放文件名，返回
        if (objIdArray.isEmpty())
        {
            acad_free(fname);
            acutPrintf(L"\nYou must pick a drawing file that contains Circles.");
            return;
        }

        //现在获得当前数据库和当前数据库的块表
        AcDbBlockTable* pThisBlockTable;
        acdbHostApplicationServices()->workingDatabase()->getSymbolTable(pThisBlockTable,AcDb::kForRead);

        //获得当前数据库的模型空间块表记录
        AcDbBlockTableRecord* pThisMsBtr;
        pThisBlockTable->getAt(ACDB_MODEL_SPACE,pThisMsBtr,AcDb::kForWrite);
        pThisBlockTable->close();

        //获得当前数据库模型空间记录的对象ＩＤ
        AcDbObjectId id = pThisMsBtr->objectId();
        pThisMsBtr->close();

        //创建长事务，这将从外部数据库中获得外部对象
        AcDbIdMapping errorMap;
        acapLongTransactionManagerPtr()->checkOut(transId,objIdArray,id,errorMap);

        //下面修改这些对象的颜色和半径
        int colorIndex;
        double radius;
        acedGetInt(L"\nEnter color number to change entityes to:",&colorIndex);
        acedGetReal(L"\nEnter circle radius:",&radius);

        //如果半径小于或等于０，则返回
        if (radius<=0)
        {
            acutPrintf(L"\nError:Radius can't less than 0!");
            return;
        }

        AcDbObject* pObj;

        //打开对象成功
        if(acdbOpenObject(pObj,transId,AcDb::kForRead) == Acad::eOk)
        {
            //获得事务的指针
            AcDbLongTransaction* pLongTrans = AcDbLongTransaction::cast(pObj);
            if (pLongTrans != NULL)
            {
                //获得工作集遍历器
                AcDbLongTransWorkSetIterator* pWorkSetIter;
                pLongTrans->newWorkSetIterator(pWorkSetIter);

                //对工作集中实体进行遍历，改变实体颜色和半径
                for (pWorkSetIter->start();!pWorkSetIter->done();pWorkSetIter->step())
                {
                    AcDbEntity* pEntity;
                    acdbOpenAcDbEntity(pEntity,pWorkSetIter->objectId(),AcDb::kForWrite);

                    //改变实体颜色和半径然后关闭对象
                    pEntity->setColorIndex(colorIndex);
                    ((AcDbCircle*)pEntity)->setRadius(radius);
                    pEntity->close();
                }
                delete pWorkSetIter;
            }
            pObj->close();
        }

        //暂停使用户能看见这种变化
        ACHAR str[50];
        acedGetString(0,L"\nSee the new colors and radius. Press retrn to back",str);

        //将实体放回原数据库
        acapLongTransactionManagerPtr()->checkIn(transId, errorMap);

        //保存原数据库
        pDb->saveAs(fname);

        //关闭数据库然后删除些对象
        delete pDb;
        pDb = NULL;

        //释放文件名
        acad_free(fname);
    }