Create a Polyline Object (.NET)

This example adds a lightweight polyline with two straight segments using the 2D coordinates (2,4), (4,2), and (6,4) to Model space.

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("AddLightweightPolyline")> _
Public Sub AddLightweightPolyline()
    '' 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 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 polyline with two segments (3 points)
        Using acPoly As Polyline = New Polyline()
            acPoly.AddVertexAt(0, New Point2d(2, 4), 0, 0, 0)
            acPoly.AddVertexAt(1, New Point2d(4, 2), 0, 0, 0)
            acPoly.AddVertexAt(2, New Point2d(6, 4), 0, 0, 0)

            '' Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly)
            acTrans.AddNewlyCreatedDBObject(acPoly, True)
        End Using

        '' Save the new object to the database
        acTrans.Commit()
    End Using
End Sub

C#

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("AddLightweightPolyline")]
public static void AddLightweightPolyline()
{
    // 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 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 polyline with two segments (3 points)
        using (Polyline acPoly = new Polyline())
        {
            acPoly.AddVertexAt(0, new Point2d(2, 4), 0, 0, 0);
            acPoly.AddVertexAt(1, new Point2d(4, 2), 0, 0, 0);
            acPoly.AddVertexAt(2, new Point2d(6, 4), 0, 0, 0);

            // Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly);
            acTrans.AddNewlyCreatedDBObject(acPoly, true);
        }

        // Save the new object to the database
        acTrans.Commit();
    }
}

VBA/ActiveX Code Reference

Sub AddLightWeightPolyline()
    Dim plineObj As AcadLWPolyline
    Dim points(0 To 5) As Double
 
    ' Define the 2D polyline points
    points(0) = 2: points(1) = 4
    points(2) = 4: points(3) = 2
    points(4) = 6: points(5) = 4
 
    ' Create a light weight Polyline object in model space
    Set plineObj = ThisDrawing.ModelSpace. _
                   AddLightWeightPolyline(points)
    ThisDrawing.Application.ZoomAll
End Sub