Erase Layers (.NET)

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.

Note: Layers 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

C#

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

Sub EraseLayer()
    On Error Resume Next
 
    Dim layerObj As AcadLayer
    Set layerObj = ThisDrawing.Layers("ABC")
 
    layerObj.Delete
End Sub

Erase Layers (.NET)

VB.NET

C#

VBA/ActiveX Code Reference

Related Concepts

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