Assign a Linetype to a Layer (.NET)

When you are defining layers, linetypes provide another way to convey visual information. A linetype is a repeating pattern of dashes, dots, and blank spaces you can use to distinguish the purpose of one line from another.

The linetype name and definition describe the particular dash-dot sequence, the relative lengths of dashes and blank spaces, and the characteristics of any included text or shapes.

Use the Linetype property to assign a linetype to a layer. This property takes the name of the linetype as input.

Note: Before a linetype can be assigned to a layer it must be defined in the drawing first.

Set the linetype for a layer

The following example creates a new layer named "ABC" and assigns it the "Center" linetype.

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
 
<CommandMethod("SetLayerLinetype")> _
Public Sub SetLayerLinetype()
    '' 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) = False Then
            Using acLyrTblRec As LayerTableRecord = New LayerTableRecord()

                '' Assign the layer a name
                acLyrTblRec.Name = sLayerName

                '' Open the Layer table for read
                Dim acLinTbl As LinetypeTable
                acLinTbl = acTrans.GetObject(acCurDb.LinetypeTableId, _
                                             OpenMode.ForRead)

                If acLinTbl.Has("Center") = True Then
                    '' Set the linetype for the layer
                    acLyrTblRec.LinetypeObjectId = acLinTbl("Center")
                End If

                '' 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
        Else
            Dim acLyrTblRec As LayerTableRecord = acTrans.GetObject(acLyrTbl(sLayerName), _
                                                                    OpenMode.ForRead)

            '' Open the Layer table for read
            Dim acLinTbl As LinetypeTable
            acLinTbl = acTrans.GetObject(acCurDb.LinetypeTableId, _
                                         OpenMode.ForRead)

            If acLinTbl.Has("Center") = True Then
                '' Upgrade the Layer Table Record for write
                acTrans.GetObject(acLyrTbl(sLayerName), OpenMode.ForWrite)

                '' Set the linetype for the layer
                acLyrTblRec.LinetypeObjectId = acLinTbl("Center")
            End If
        End If

        '' 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;
 
[CommandMethod("SetLayerLinetype")]
public static void SetLayerLinetype()
{
    // 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) == false)
        {
            using (LayerTableRecord acLyrTblRec = new LayerTableRecord())
            {
                // Assign the layer a name
                acLyrTblRec.Name = sLayerName;

                // Open the Layer table for read
                LinetypeTable acLinTbl;
                acLinTbl = acTrans.GetObject(acCurDb.LinetypeTableId,
                                                OpenMode.ForRead) as LinetypeTable;

                if (acLinTbl.Has("Center") == true)
                {
                    // Set the linetype for the layer
                    acLyrTblRec.LinetypeObjectId = acLinTbl["Center"];
                }

                // 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);
            }
        }
        else
        {
            LayerTableRecord acLyrTblRec = acTrans.GetObject(acLyrTbl[sLayerName],
                                            OpenMode.ForRead) as LayerTableRecord;

            // Open the Layer table for read
            LinetypeTable acLinTbl;
            acLinTbl = acTrans.GetObject(acCurDb.LinetypeTableId,
                                            OpenMode.ForRead) as LinetypeTable;

            if (acLinTbl.Has("Center") == true)
            {
                // Upgrade the Layer Table Record for write
                acTrans.GetObject(acLyrTbl[sLayerName], OpenMode.ForWrite);

                // Set the linetype for the layer
                acLyrTblRec.LinetypeObjectId = acLinTbl["Center"];
            }
        }

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

VBA/ActiveX Code Reference

Sub SetLayerLinetype()
    On Error Resume Next
    Dim layerObj As AcadLayer
 
    Set layerObj = ThisDrawing.Layers.Add("ABC")
    layerObj.Linetype = "Center"
End Sub