Ok, I got it only thing that is being required
1.) is to create a class library
2.) Then need to enter the above code in the class.
3.) Build your project by pressing F5.
4.) A DLL will be created in the bin/debug/ folder of your project
5.) Open Autocad.
6.) Write netload command.
7.) Select the DLL created and then write command "LISTGEN" and than kaboom it will show all the objects in your project.