Creating and accessing layer filter information

By Balaji Ramamoorthy

Here is a ObjectARX and .Net sample code to create and access the layer filters. A simple trick to know the layer filter expression that will suit your needs, is to create a layer filter in AutoCAD and use this code to find the filter expression for it. This can then be used in your code to create a new layer filter.

Using ObjectARX :

Acad::ErrorStatus es = Acad::eOk;

AcDbDatabase *pDb =

             acdbHostApplicationServices()->workingDatabase();

 

AcLyLayerFilterManager *pLayerFilterManager =

                               aclyGetLayerFilterManager(pDb);

 

AcLyLayerFilter *pRoot = NULL;

AcLyLayerFilter *pCurrent = NULL;

es = pLayerFilterManager->getFilters(pRoot, pCurrent);

if(es != Acad::eOk)

    return;

 

if(pRoot != NULL)

{

    AcArray<AcLyLayerFilter *> filters;

    filters = pRoot->getNestedFilters();

 

    // Lets find out about the root filter

    acutPrintf

            (

                ACRX_T("\n(Root) Name : %s Expr : %s"),

                pRoot->name(),

                pRoot->filterExpression()

            );

 

    // Lets find out about all the filters

    for(int i=0; i < filters.length();i++)

    {

        acutPrintf

                (

                    ACRX_T("\nName : %s Expr : %s"),

                    filters.at(i)->name(),

                    filters.at(i)->filterExpression()

                );

    }

 

    // Lets find out about the current filter

    if(pCurrent != NULL)

    {

        acutPrintf

                (

                    ACRX_T("\n(Current) Name : %s Expr : %s"),

                    pCurrent->name(),

                    pCurrent->filterExpression()

                );

    }

 

    // Create and add a new layer filter

    AcLyLayerFilter *pMyLyFilter = new AcLyLayerFilter();

    pMyLyFilter->setName(ACRX_T("MyLyFilter"));

    pMyLyFilter->setFilterExpression(ACRX_T("NAME == \"*Test*\""));

 

    es = pRoot->addNested(pMyLyFilter);

    es = pLayerFilterManager->setFilters(pRoot, pMyLyFilter);

 

    delete pRoot;

}

Using AutoCAD .Net API :

using Autodesk.AutoCAD.LayerManager;

[CommandMethod("CreateLayerFilter")]

public void CreateLayerFilter()

{

    Document doc

                = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    LayerFilterTree filterTree = db.LayerFilters;

    LayerFilterCollection filters

                            = filterTree.Root.NestedFilters;

 

    // Lets find out about the root filter

    ed.WriteMessage

            (

                String.Format("\n(Root) Name : {0} Expr : {1}",

                db.LayerFilters.Root.Name,

                db.LayerFilters.Root.FilterExpression)

            );

 

    // Lets find out about all the filters

    foreach(LayerFilter f in filters)

    {

        ed.WriteMessage

                (

                    String.Format("\nName : {0} Expr : {1}",

                    f.Name,

                    f.FilterExpression)

                );

    }

 

    // Lets find out about the current filter

    if(db.LayerFilters.Current != null)

    {

        ed.WriteMessage

        (

            String.Format("\n(Current) Name : {0} Expr : {1}",

            db.LayerFilters.Current.Name,

            db.LayerFilters.Current.FilterExpression)

        );

    }

 

    // Create and add a new layer filter

    LayerFilter layerFilter = new LayerFilter();

    layerFilter.Name = "MyLyFilter";

    layerFilter.FilterExpression = "NAME == \"*Test*\"";

    filters.Add(layerFilter);

 

    // Set the changed layer filters tree to the database

    db.LayerFilters = filterTree;

}

Posted at 07:26 AM in .NET, AutoCAD, Balaji Ramamoorthy, ObjectARX | Permalink

Delete layer filters using ObjectARX

by Fenton Webb

Issue

I have a customer who uses many dwgs with many filters on the layer. How can I delete the filters using a program?

Solution

Layer filters exist as AcDbXRecord entries in two dictionaries (with name "ACAD_LAYERFILTERS" and "ACLYDICTIONARY") contained in the extension dictionary of Layer Table. To delete the layer filters, you need to iterate through the "ACAD_LAYERFILTERS" and "ACLYDICTIONARY" dictionaries and delete all AcDbXRecords.

The code below opens a dummy drawing and deletes all layer filters inside of the drawing:

static void ASDKLayerFilterDelete_DeleteLayerFilters(void)

{

  // Set constructor parameter to kFalse so that the

  // database will be constructed empty.  This way only

  // what is read in will be in the database.

  AcDbDatabase *pDb = new AcDbDatabase(Adesk::kFalse);

 

  // The AcDbDatabase::readDwgFile() function

  // automatically appends a DWG extension if it is not

  // specified in the filename parameter.

  pDb->readDwgFile(_T("c:\\drawing1.dwg"));

  // ensure the whole dwg is read

  pDb->closeInput(true);

 

  // Get the Layer Table

  AcDbLayerTablePointer pLyrTbl(pDb->layerTableId(), AcDb::kForRead);

  if (pLyrTbl.openStatus() == Acad::eOk)

  {

    // Get Extention dictionary

    AcDbObjectId pExtDicId = pLyrTbl->extensionDictionary();

 

    if(pExtDicId.isValid())

    {        

      AcDbDictionaryPointer pDict(pExtDicId,AcDb::kForRead);

      if(Acad::eOk == pDict.openStatus())

      {

        // Get Layer Filter Dictionary from extension dictionary

        AcDbObjectId pObjId;

        pDict->getAt(_T("ACAD_LAYERFILTERS"),pObjId);

 

        if(pObjId.isValid())

        {

          AcDbDictionaryPointer pFiltDict(pObjId,AcDb::kForRead);

 

          if(Acad::eOk == pFiltDict.openStatus())

          {

            // Get objects in layer filter dictionary

            AcDbObjectId filtObjId;

            AcDbDictionaryIterator *pItr = pFiltDict->newIterator();

            if (NULL != pItr)

            {

              for(;!pItr->done();pItr->next())

              {

                AcDbObjectPointer<AcDbXrecord> pLyrFltr(pItr->objectId(),AcDb::kForWrite);

                if(Acad::eOk == pLyrFltr.openStatus())

                {

                  pLyrFltr->erase();

                }

              }

              delete pItr;

            }

          }

        }    

 

        pDict->getAt(_T("ACLYDICTIONARY"),pObjId);

 

 

        if(pObjId.isValid())

        {

          AcDbDictionaryPointer pFiltDict(pObjId,AcDb::kForRead);

          if(Acad::eOk == pFiltDict.openStatus())

          {

            // Get objects in layer filter dictionary

            AcDbObjectId filtObjId;

 

            AcDbDictionaryIterator *pItr = pFiltDict->newIterator();

            if(NULL != pItr)

            {

              for(;!pItr->done();pItr->next())

              {

                AcDbObjectPointer<AcDbXrecord> pLyrFltr(pItr->objectId(),AcDb::kForWrite);

                if(Acad::eOk == pLyrFltr.openStatus())

                {

                  pLyrFltr->erase();

                }       

              }

              delete pItr;

            }

          }    

        }

      }

    }  

  } 

 

  Acad::ErrorStatus es = pDb->saveAs(_T("c:\\drawing1.dwg"));

  delete pDb; 

}

Posted at 02:10 PM in 2010, 2011, 2012, 2013, AutoCAD, Fenton Webb, ObjectARX | Permalink