How to Implement cascading single drop list in C#

http://www.c-sharpcorner.com/article/creating-simple-cascading-dropdownlist-in-mvc/

 

http://www.c-sharpcorner.com/UploadFile/sourabh_mishra1/cascading-dropdownlist-in-Asp-Net-mvc/ 

Refer below link which explains well about cascade drop down list.

http://www.c-sharpcorner.com/UploadFile/b926a6/cascading-dropdown-list-in-three-tier-Asp-Net-application/ 

 

If you want to implement state in the same country drop down list, I think it is not possible, you have to take another drop down for state which will be depending on country. If you want to show under country itself, then better you use tree view.