CODEWITHSUNDEEP
c#autocadautocad-plugin
Umar
Umar

Reputation: 487

Need to fetch count of objects created from a class in AutoCAD Civil3D

It's very specific to AutoCAD SDK, developing an add-in for AutoCAD. I have loaded some DWG files in to a drawing and created some objects of the classes loaded. When these objects are created I add an Xdata containing some information on BlockTableRecord. Now, I need to remove BlockTableRecords for the objects that have been deleted from the drawing. I am getting a call back from AutoCAD when document is saved. In this call back, I am trying to traverse through all Block Table Records to find the records with our information. And the records that contain information that they were created using my add-in, I am trying to see the number of objects created from this record item. If there exists none, I will delete the block table record or at least update our footprint.

Here I am unable to get the count of objects created from one specific table record. Here's what I have done so far.

private static void CommandExecutionCallBack(object sender, CommandEventArgs e)
{
    string commando = e.GlobalCommandName.ToLower();
    if (commando.Contains("save"))
    {
        Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;
        var documentManager = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager;
        Editor ed = doc.Editor;
        Database db = doc.Database;
        Autodesk.AutoCAD.DatabaseServices.TransactionManager tm = db.TransactionManager;
        using (Transaction myT = tm.StartTransaction())
        {
            BlockTable bt = (BlockTable)tm.GetObject(db.BlockTableId, OpenMode.ForRead, false);
            SymbolTableEnumerator enumerator = bt.GetEnumerator();
            while (enumerator.MoveNext())
            {
                BlockTableRecord btr = tm.GetObject(enumerator.Current, OpenMode.ForRead, false) as BlockTableRecord;
                ResultBuffer xdata = btr.GetXDataForApplication(REGAPP_NAME);
                if (null != xdata)
                {

                    //Here I am trying to fetch the objects that exist against the selected btr.
                    AcadApplication acApp = Autodesk.AutoCAD.ApplicationServices.Application.AcadApplication as AcadApplication;
                    AcadDocument thisDrawing = acApp.ActiveDocument;


                    thisDrawing.SendCommand("(command MAPSELECTCLASSIFIED " + btr.Name + ")" + Environment.NewLine);
                    AcadSelectionSet selectionSet = thisDrawing.PickfirstSelectionSet;

                    //I am always getting selectionSet.Count as zero.
                    MessageBox.Show(btr.Name + " -> SelectionSet Count: " + selectionSet.Count.ToString());
                }
                else
                {
                    //Will ignore this condition. The current btr is not created by our add-in
                }
            }
        }
    }
}

Any help in this regard would be appreciated.

I have taken some help from AutoCAD forum, https://forums.autodesk.com/t5/net/how-to-find-and-export-object-classess-from-drawing/m-p/5814774#M45948

Regards, Umar

Upvotes: 0

Views: 532

Answers (1)

gileCAD
gileCAD

Reputation: 2493

Delating unreferenced BlockTableRecord (or any other SymbolTableRecord) is commonly called: Purge. The Database class provide a Purge() method which can be used to get the "purgeable" objects.

    private static ObjectIdCollection GetPurgeableBlocks(Database db)
    {
        var ids = new ObjectIdCollection();
        using (var tr = new OpenCloseTransaction())
        {
            var bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);
            foreach (ObjectId id in bt)
            {
                var btr = (BlockTableRecord)tr.GetObject(id, OpenMode.ForRead);
                if (btr.GetXDataForApplication(REGAPP_NAME) != null)
                {
                    ids.Add(id);
                }
            }
            tr.Commit();
        }
        db.Purge(ids);
        return ids;
    }

Upvotes: 0

Related Questions