the first c# dll of autocad

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using Autodesk.AutoCAD.ApplicationServices;
 7 using Autodesk.AutoCAD.EditorInput;
 8 using Autodesk.AutoCAD.Runtime;
 9 
10 namespace test
11 {
12 
13     public class Class1
14     {
15         [CommandMethod("Hey")]
16         public void Hello()
17         {
18             Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
19             ed.WriteMessage("Hello,dotnet!");
20         }
21 
22     }
23 }