输出CAD图中第一个图元类型——c#实现

复制改图元到一个新dwg中，启动代码可实现

如下图设置：

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

namespace ClassLibrary4
{
    public class Class1
    {

        [CommandMethod("ListEntities")]
        public static void ListEntities()
        {
            // Get the current document and database, and start a transaction
            Document acDoc = Application.DocumentManager.MdiActiveDocument;
            Database acCurDb = acDoc.Database;

            using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
            {
                // 以只读方式打开块表记录   Open the Block table record for rea