Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

<CommandMethod("AddMyLayer")> _

Public Sub AddMyLayer()

  ''获得当前文档和数据库，并启动一个事务   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()

      ''返回当前数据库的层表   Returns the layer table for the current database

      Dim acLyrTbl As LayerTable

      acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId, _

                                   OpenMode.ForRead)

      ''检验名字为 MyLayer 的图层是否已经存在在层表中 Check to see if MyLayer exists in the Layer table

      If Not acLyrTbl.Has("MyLayer") Then

          '' 以写的方式打开层表 Open the Layer Table for write

          acLyrTbl.UpgradeOpen()

          '' 创建一个新的层表记录并命名为“MyLayer”  Create a new layer table record and name the layer "MyLayer"

          Dim acLyrTblRec As LayerTableRecord = New LayerTableRecord

          acLyrTblRec.Name = "MyLayer"

          '' 添加新的层表记录到层表和事务中 Add the new layer table record to the layer table and the transaction

          acLyrTbl.Add(acLyrTblRec)

          acTrans.AddNewlyCreatedDBObject(acLyrTblRec, True)

          '' 确认所做的修改  Commit the changes

          acTrans.Commit()

      End If

      '' 销毁事务  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

  }

}