How to prevent certain entities from being saved to a DWG file using ObjectARX

by Fenton Webb

If you want to be able to prevent certain entities from being saved out to a DWG file, or rather, exclude certain entities from a DWG Save operation you can use an AcEdEditorReactor to do the job…

Here’s some code which shows how you might do it…

// not MDI aware, use CDocData for MSI document aware global vars    static AcDbObjectIdArray gEntityIdsNotToSave;    // test command    void test()    {      ads_name ss,ename;      // select some entities to "not" save       if (ads_ssget(NULL,NULL,NULL,NULL,ss) != RTNORM)        return;           // if the selection was successful      long len;      // get the total number of items selected in the selection set      ads_sslength(ss,&len);      AcDbObjectId id;      // now loop through them all      for (long i=0; iaddReactor(this);      }      ~NoSave()      {        acedEditor->removeReactor(this);      }           virtual void beginSave(AcDbDatabase* pDwg, const TCHAR* pIntendedName);      virtual void saveComplete(AcDbDatabase* pDwg, const TCHAR* pActualName);      void HideEntities(Adesk::Boolean hide)      {        // make sure we have some entities to "not" save        if (gEntityIdsNotToSave.length() == 0)          return;             // do a quick check if we are saving the database of interest        bool bTheOne = gEntityIdsNotToSave[0].database() == pDwg;        // if not the one        if (!bTheOne)          return;             // otherwise loop our entities and erase them        for (int i=0; ierase(hide);        }             // make sure that the graphics pipeline is updated         // because AutoCAD isn't expecting the display list to have         // changed at this point        actrTransactionManager->flushGraphics();        acedUpdateDisplay();      }    };         // beginSave:erase the entities in question so they don't get saved    void NoSave::beginSave(AcDbDatabase* pDwg, const TCHAR* pIntendedName)    {      HideEntities(true);    }         // saveComplete: restore the entities by un-erasing them    void NoSave::saveComplete(AcDbDatabase* pDwg, const TCHAR* pActualName)    {      HideEntities(false);    }         // create global instance of the editor reactor    static NoSave g_noSave;