In Your application if you have more than one DBML file then each DBML file will contain app.config for each DBML file. consider the WPF application it will be not possible for you to change the client app.config connection string on deployment. when your application will be ready for deployment take a copy of your solution from your source control. bcoz now you are going to perform many change on your app.config. 1. if you have more than one project then you have change the all project output type as a class library except the start up project. right click on the project > properties > change the output as class library 2. Click on setting > right click on the connection string click remove string. if you have more than one then remove all as same. 3. if you have app.xaml . right click and exclude it from project. 4. open your DBML file > right click > properties > expand the connection > select application string as false. ...
Work smarter, not harder.