Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

<CommandMethod("AddMyLayer")> _

Public Sub AddMyLayer()

  '' Get the current document and database, and start a transaction

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

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

      '' Returns the layer table for the current database

      Dim acLyrTbl As LayerTable

      acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId, _

                                   OpenMode.ForRead)

      '' Check to see if MyLayer exists in the Layer table

      If Not acLyrTbl.Has("MyLayer") Then

          '' Open the Layer Table for write

          acLyrTbl.UpgradeOpen()

          '' Create a new layer table record and name the layer "MyLayer"

          Dim acLyrTblRec As LayerTableRecord = New LayerTableRecord

          acLyrTblRec.Name = "MyLayer"

          '' Add the new layer table record to the layer table and the transaction

          acLyrTbl.Add(acLyrTblRec)

          acTrans.AddNewlyCreatedDBObject(acLyrTblRec, True)

          '' Commit the changes

          acTrans.Commit()

      End If

      '' Dispose of the transaction

  End Using

End Sub

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

[CommandMethod("AddMyLayer")]

public static void AddMyLayer()

{

  // Get the current document and database, and start a transaction

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

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

  {

      // Returns the layer table for the current database

      LayerTable acLyrTbl;

      acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId,

                                   OpenMode.ForRead) as LayerTable;

      // Check to see if MyLayer exists in the Layer table

      if (acLyrTbl.Has("MyLayer") != true)

      {

          // Open the Layer Table for write

          acLyrTbl.UpgradeOpen();

          // Create a new layer table record and name the layer "MyLayer"

          LayerTableRecord acLyrTblRec = new LayerTableRecord();

          acLyrTblRec.Name = "MyLayer";

          // Add the new layer table record to the layer table and the transaction

          acLyrTbl.Add(acLyrTblRec);

          acTrans.AddNewlyCreatedDBObject(acLyrTblRec, true);

          // Commit the changes

          acTrans.Commit();

      }

      // Dispose of the transaction

  }

}