c# - Namespace, folders and classes in visual studio 2013 -

i have solution 4 projects in them. main or startup project , child projects. startup project mdi form has menus , child projects called main project menus. in wise, main mdi project has references child projects. instance, in mdi reference folder following child projects dlls, business.child.dal, business.child.views, business.child.bl, business.child.bi. in mdi

using business.child.dal using business.child.views using business.child.bl using business.child.bi 

now happening is, bl , bi not coming when type using buinsess.child...., bl , bi not appear. classes in bl not accessible now. can't figure out happening , need here. people.

what realize that, class 'businessproperties' needed made public. after making public class businessproperties bl folder visible in main mdi app.

using business.child.bl  

i able have reference.