Understand How AutoCAD Saves Layer States

AutoCAD saves layer setting information in an extension dictionary of the Layers table object. When you first save a layer state, AutoCAD does the following:

Creates an extension dictionary on the Layers table.
Creates a Dictionary object named ACAD_LAYERSTATE in the extension dictionary.
Stores the properties of each layer in the drawing in an XRecord object in the ACAD_LAYERSTATE dictionary. AutoCAD stores all layer settings in the XRecord, but identifies the specific settings you chose to save. When you restore the layer settings, AutoCAD restores only the settings you chose to save.

Each time you save another layer setting in the drawing, AutoCAD creates another XRecord object describing the saved settings and stores the XRecord in the ACAD_LAYERSTATE dictionary. The following diagram illustrates the process.

You do not need (and should not try) to directly manipulate the entries when working with layer states. Use the functions of the LayerStateManager object to access the dictionary. Once you have a reference to the dictionary, you can step through each of the entries which are represented as DBDictionaryEntry objects.

List the saved layer states in a drawing

If layer states have been saved in the current drawing, the following code lists the names of all saved layer states:

VB.NET

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

<CommandMethod("ListLayerStates")> _

Public Sub ListLayerStates()

  '' Get the current document and database

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  '' Start a transaction

  Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

      Dim acLyrStMan As LayerStateManager

      acLyrStMan = acCurDb.LayerStateManager

      Dim acDbDict As DBDictionary

      acDbDict = acTrans.GetObject(acLyrStMan.LayerStatesDictionaryId(True), _

                                   OpenMode.ForRead)

      Dim sLayerStateNames As String = ""

      For Each acDbDictEnt As DBDictionaryEntry In acDbDict

          sLayerStateNames = sLayerStateNames & vbLf & acDbDictEnt.Key

      Next

      Application.ShowAlertDialog("The saved layer settings in this drawing are:" & _

                                  sLayerStateNames)

      '' Dispose of the transaction

  End Using

End Sub

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

[CommandMethod("ListLayerStates")]

public static void ListLayerStates()

  // Get the current document and database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())

      LayerStateManager acLyrStMan;

      acLyrStMan = acCurDb.LayerStateManager;

      DBDictionary acDbDict;

      acDbDict = acTrans.GetObject(acLyrStMan.LayerStatesDictionaryId(true),

                                   OpenMode.ForRead) as DBDictionary;

      string sLayerStateNames = "";

      foreach (DBDictionaryEntry acDbDictEnt in acDbDict)

          sLayerStateNames = sLayerStateNames + "\n" + acDbDictEnt.Key;

      Application.ShowAlertDialog("The saved layer settings in this drawing are:" +

                                  sLayerStateNames);

      // Dispose of the transaction

VBA/ActiveX Code Reference