When we use the Entity Framework (EF) in multilayer information systems sometimes we want to extend classes generated by EF by adding some common properties or functions. Such operation cant be conduct on *.edmx data model so we need to make some improvement in our solution. Lets begin... Lets assumed that in our soulution we have only three layer (three project):Client console application which has reference to the second layer  - 'ConsoleApplication' project nameClass library project with class i...