Erase Layers

You can erase a layer at any time during a drawing session. You cannot erase the current layer, layer 0, an xref-dependent layer, or a layer that contains objects.

To erase a layer, use the Erase method. It is recommended to use the Purge function to verify that the layer can be purged, along with verifying that it is not layer 0, Defpoints, or the current layer.

NoteLayers referenced by block definitions, along with the special layer named DEFPOINTS, cannot be deleted even if they do not contain visible objects.

VB.NET

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

<CommandMethod("EraseLayer")> _

Public Sub EraseLayer()

  '' 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()

      '' Open the Layer table for read

      Dim acLyrTbl As LayerTable

      acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId, _

                                   OpenMode.ForRead)

      Dim sLayerName As String = "ABC"

      If acLyrTbl.Has(sLayerName) = True Then

          '' Check to see if it is safe to erase layer

          Dim acObjIdColl As ObjectIdCollection = New ObjectIdCollection()

          acObjIdColl.Add(acLyrTbl(sLayerName))

          acCurDb.Purge(acObjIdColl)

          If acObjIdColl.Count > 0 Then

              Dim acLyrTblRec As LayerTableRecord

              acLyrTblRec = acTrans.GetObject(acObjIdColl(0), OpenMode.ForWrite)

Try

                  '' Erase the unreferenced layer

                  acLyrTblRec.Erase(True)

                  '' Save the changes and dispose of the transaction

                  acTrans.Commit()

              Catch Ex As Autodesk.AutoCAD.Runtime.Exception

                  '' Layer could not be deleted

                  Application.ShowAlertDialog("Error:\n" + Ex.Message)

              End Try

          End If

      End If

  End Using

End Sub

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

[CommandMethod("EraseLayer")]

public static void EraseLayer()

  // Get the current document and database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

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

      // Open the Layer table for read

      LayerTable acLyrTbl;

      acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId,

                                   OpenMode.ForRead) as LayerTable;

      string sLayerName = "ABC";

      if (acLyrTbl.Has(sLayerName) == true)

          // Check to see if it is safe to erase layer

          ObjectIdCollection acObjIdColl = new ObjectIdCollection();

          acObjIdColl.Add(acLyrTbl[sLayerName]);

          acCurDb.Purge(acObjIdColl);

          if (acObjIdColl.Count > 0)

              LayerTableRecord acLyrTblRec;

              acLyrTblRec = acTrans.GetObject(acObjIdColl[0],

                                              OpenMode.ForWrite) as LayerTableRecord;

try

                  // Erase the unreferenced layer

                  acLyrTblRec.Erase(true);

                  // Save the changes and dispose of the transaction

                  acTrans.Commit();

              catch (Autodesk.AutoCAD.Runtime.Exception Ex)

                  // Layer could not be deleted

                  Application.ShowAlertDialog("Error:\n" + Ex.Message);

VBA/ActiveX Code Reference