D.B disconnect after run application

Question

Good Times all

Actually, these problem is a first time faced me. I worked in web development for long time, but I don't know If someone faced a same problem befor, 

 

Introduction:

I've a web app, and D.B connecte with site application, If i open a data base to add make (CRUD) operations on data tables  or add/remove table, a Database opening before run application in (SQL server data base explore) in visual Studio 2012.

 

Problem description:

when I run app. and logging to site adminstration, if I select a to add data to data base, a message show(No D.B) connection).

 

You can see a capture screen to show details.

 

Thanks