Create and Name Layers (.NET)

You can create new layers and assign color and linetype properties to those layers. Each individual layer is part of the Layers table. Use the Add function to create a new layer and add it to the Layers table.

You can assign a name to a layer when it is created. To change the name of a layer after it has been created, use the Name property. Layer names can include up to 255 characters and contain letters, digits, and the special characters dollar sign ($), hyphen (-), and underscore (_).

Create a new layer, assign it the color green, and add an object to the layer

The following code creates a new layer and circle object. The new layer is assigned the color green. The circle is assigned to the layer, and the color of the circle changes accordingly.

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.Colors
 
<CommandMethod("CreateAndAssignALayer")> _
Public Sub CreateAndAssignALayer()
    '' 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 = "Center"

        If acLyrTbl.Has(sLayerName) = False Then
            Using acLyrTblRec As LayerTableRecord = New LayerTableRecord()

                '' Assign the layer the ACI color 3 and a name
                acLyrTblRec.Color = Color.FromColorIndex(ColorMethod.ByAci, 3)
                acLyrTblRec.Name = sLayerName

                '' Upgrade the Layer table for write
                acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForWrite)

                '' Append the new layer to the Layer table and the transaction
                acLyrTbl.Add(acLyrTblRec)
                acTrans.AddNewlyCreatedDBObject(acLyrTblRec, True)
            End Using
        End If

        '' Open the Block table for read
        Dim acBlkTbl As BlockTable
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _
                                     OpenMode.ForRead)

        '' Open the Block table record Model space for write
        Dim acBlkTblRec As BlockTableRecord
        acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
                                        OpenMode.ForWrite)

        '' Create a circle object
        Using acCirc As Circle = New Circle()
            acCirc.Center = New Point3d(2, 2, 0)
            acCirc.Radius = 1
            acCirc.Layer = sLayerName

            acBlkTblRec.AppendEntity(acCirc)
            acTrans.AddNewlyCreatedDBObject(acCirc, True)
        End Using

        '' Save the changes and dispose of the transaction
        acTrans.Commit()
    End Using
End Sub

C#

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Colors;
 
[CommandMethod("CreateAndAssignALayer")]
public static void CreateAndAssignALayer()
{
    // 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 = "Center";

        if (acLyrTbl.Has(sLayerName) == false)
        {
            using (LayerTableRecord acLyrTblRec = new LayerTableRecord())
            {
                // Assign the layer the ACI color 3 and a name
                acLyrTblRec.Color = Color.FromColorIndex(ColorMethod.ByAci, 3);
                acLyrTblRec.Name = sLayerName;

                // Upgrade the Layer table for write
                acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForWrite);

                // Append the new layer to the Layer table and the transaction
                acLyrTbl.Add(acLyrTblRec);
                acTrans.AddNewlyCreatedDBObject(acLyrTblRec, true);
            }
        }

        // Open the Block table for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,
                                        OpenMode.ForRead) as BlockTable;

        // Open the Block table record Model space for write
        BlockTableRecord acBlkTblRec;
        acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                                        OpenMode.ForWrite) as BlockTableRecord;

        // Create a circle object
        using (Circle acCirc = new Circle())
        {
            acCirc.Center = new Point3d(2, 2, 0);
            acCirc.Radius = 1;
            acCirc.Layer = sLayerName;

            acBlkTblRec.AppendEntity(acCirc);
            acTrans.AddNewlyCreatedDBObject(acCirc, true);
        }

        // Save the changes and dispose of the transaction
        acTrans.Commit();
    }
}

VBA/ActiveX Code Reference

Sub CreateAssignALayer()
    ' Create a new layer and assign it the color red
    Dim layerObj As AcadLayer
    Set layerObj = ThisDrawing.Layers.Add("Center")
    layerObj.color = acRed
 
    ' Create a circle
    Dim circleObj As AcadCircle
    Dim center(0 To 2) As Double
    Dim radius As Double
    center(0) = 2: center(1) = 2: center(2) = 0
    radius = 1
    Set circleObj = ThisDrawing.ModelSpace. _
                    AddCircle(center, radius)
 
    ' Place the circle on the Center layer
    circleObj.Layer = "Center"
 
    circleObj.Update
End Sub