Unload all the PDF underlay

By Virupaksha Aithal

Below code shows the procedure to unload all the PDF underlays. It is required to update the corresponding PDF underlay references , so that AutoCAD can update the model space graphics. For this, the “PdfDefinition.GetPersistentReactorIds” API is used to get all the references of the PDF underlay definition.

[CommandMethod("PdfUnload")]
static public void PdfUnload()
{
    Document doc = Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
    Editor ed = doc.Editor;

    using (Transaction Tx = db.TransactionManager.StartTransaction())
    {
        DBDictionary nod = Tx.GetObject(db.NamedObjectsDictionaryId, 
                                                    OpenMode.ForRead) as DBDictionary;

        string defDictKey = UnderlayDefinition.GetDictionaryKey(typeof(PdfDefinition));

        if (!nod.Contains(defDictKey))
            return;

        DBDictionary pdfDict = Tx.GetObject(nod.GetAt(defDictKey), 
                                                    OpenMode.ForWrite) as DBDictionary;

        foreach (DBDictionaryEntry entry in pdfDict)
        {
            PdfDefinition entryObj = Tx.GetObject(entry.Value, 
                                                    OpenMode.ForWrite) as PdfDefinition;
            entryObj.Unload();

            ObjectIdCollection collection = entryObj.GetPersistentReactorIds();

            foreach (ObjectId id in collection)
            {
                DBObject temObject = Tx.GetObject(id, OpenMode.ForRead);

                if (temObject is PdfReference)
                {
                    PdfReference pdfref = temObject as PdfReference;
                    pdfref.UpgradeOpen();
                    pdfref.RecordGraphicsModified(true);
                }
            }
        }
        Tx.Commit();
    }
}