代码创建多重引线样式和绘制多重引线

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.Colors;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;
using 创建多重引线;

[assembly: CommandClass(typeof (Class1))]

namespace 创建多重引线
{
    public class Class1
    {
        [CommandMethod("AddML")]
        public static void DrawMleader()
        {
            var MLStyleId = CreateMleaderStyle("xuguang");
            //获取当前数据库
            var acDoc = Application.DocumentManager.MdiActiveDocument;
            var acCurDb = acDoc.Database;
            //启动事务
            using (var acTrans = acCurDb.TransactionManager.StartTransaction())
            {
                //以读模式打开块表
                var acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;

                //以写模式打开块表记录模型空间
                var acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                    OpenMode.ForWrite) as BlockTableRecord;

                var pMLeader = new MLeader();
                pMLeader.SetDatabaseDefaults();
                pMLeader.MLeaderStyle = MLStyleId;
                var pos = new Point3d(200, 200, 200);
                var posTmp = new Point3d(220, 220, 0);
                var sn = pMLeader.AddLeaderLine(pos);
                pMLeader.AddFirstVertex(sn, pos);
                pMLeader.SetFirstVertex(sn, pos);
                pMLeader.SetLastVertex(sn, posTmp);

                //创建多行文字（MText）注释
                var pMtext = new MText();
                pMtext.Contents = "创建多重引线";
                pMtext.TextHeight = 3;
                pMtext.TextStyleId = acCurDb.Textstyle;

                pMtext.Location = posTmp;
                pMLeader.MText = pMtext;
              
                //添加新对象到模型空间，记录事务
                acBlkTblRec.AppendEntity(pMLeader);
                acTrans.AddNewlyCreatedDBObject(pMLeader, true);

                //提交修改，回收内存
                acTrans.Commit();
            }
            acDoc.Editor.Regen();
        }

        private static ObjectId CreateMleaderStyle(string MlName)
        {
            var acDoc = Application.DocumentManager.MdiActiveDocument;
            var db = HostApplicationServices.WorkingDatabase;

            using (var acTrans = acDoc.TransactionManager.StartTransaction())
            {
                var DbDictionary = acTrans.GetObject(db.MLeaderStyleDictionaryId, OpenMode.ForWrite) as DBDictionary;
                //获取所有样式
                if (DbDictionary.Contains(MlName))
                {
                    return DbDictionary.GetAt(MlName);
                }
                var newMleadStyle = new MLeaderStyle();
                newMleadStyle.TextAlignAlwaysLeft = true;
                newMleadStyle.Annotative = AnnotativeStates.True;
                newMleadStyle.DrawMLeaderOrderType = DrawMLeaderOrderType.DrawLeaderFirst;
                newMleadStyle.TextAttachmentType = TextAttachmentType.AttachmentMiddle; //Text连接方式
                newMleadStyle.TextAttachmentDirection = TextAttachmentDirection.AttachmentHorizontal; //文字水平排列
                newMleadStyle.TextAlignmentType = TextAlignmentType.CenterAlignment; //Text排列方式
                newMleadStyle.LeaderLineColor =
                    Color.FromColorIndex(ColorMethod.ByLayer, 256);
                newMleadStyle.LeaderLineType = LeaderType.StraightLeader;
                newMleadStyle.ContentType = ContentType.MTextContent;
                newMleadStyle.ArrowSize = 3.0; //箭头大小
                newMleadStyle.BreakSize = 0.6; //基线打断大小
                newMleadStyle.DoglegLength = 1.25; //基线距离
                newMleadStyle.EnableLanding = true;
                newMleadStyle.EnableDogleg = true; //显示基线
                newMleadStyle.EnableFrameText = true; //显示文本框
                newMleadStyle.LandingGap = 1; //基线间隙
                newMleadStyle.MaxLeaderSegmentsPoints = 2; //最大引线点数
                newMleadStyle.TextStyleId = acDoc.Database.Textstyle; //文字样式
                newMleadStyle.TextHeight = 3.0;
                newMleadStyle.PostMLeaderStyleToDb(db, MlName);
                newMleadStyle.DowngradeOpen();
                acTrans.Commit();
                return newMleadStyle.ObjectId;
            }
        }
    }
}