Desenhando um quadrado no AutoCAD com ObjectARX: Parte I

Post3-FullCode.cs

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DesenharQuadrado
{
    public class AuxiliarAutoCAD
    {
        [CommandMethod("DesenharQuadrado")]
        public void DesenharQuadrado()
        {

            var pontoA = new Point3d(0, 100, 0);
            var pontoB = new Point3d(100, 100, 0);
            var pontoC = new Point3d(0, 0, 0);
            var pontoD = new Point3d(100, 0, 0);

            var retaAB = new Line(pontoA, pontoB);
            var retaAC = new Line(pontoA, pontoC);
            var retaBD = new Line(pontoB, pontoD);
            var retaCD = new Line(pontoC, pontoD);

            var document = Application.DocumentManager.MdiActiveDocument;

            using (var transaction = document.TransactionManager.StartTransaction())
            {
                var blockTable = transaction.GetObject(document.Database.BlockTableId, OpenMode.ForRead) as BlockTable;
                var blockTableRecord = transaction.GetObject(blockTable[BlockTableRecord.ModelSpace], OpenMode.ForWrite) as BlockTableRecord;

                blockTableRecord.AppendEntity(retaAB);
                transaction.AddNewlyCreatedDBObject(retaAB, true);

                blockTableRecord.AppendEntity(retaAC);
                transaction.AddNewlyCreatedDBObject(retaAC, true);

                blockTableRecord.AppendEntity(retaBD);
                transaction.AddNewlyCreatedDBObject(retaBD, true);

                blockTableRecord.AppendEntity(retaCD);
                transaction.AddNewlyCreatedDBObject(retaCD, true);

                transaction.Commit();

                transaction.Commit();
            }

            document.Editor.WriteMessage("Comando efetuado com sucesso.");
        }
    }
}