编译项目后，Visual Studio C＃2010 Express引用无效

Question

I have two projekts in my c# solution explorer. The first project contains helper classes like a login to the database with NHibernate and some other stuff. My second project contains the main files for my programm like the GUI, their controllers etc.

The second project references on the first project because I want to use functions of my helper classes in the second project. I am able to compile the helper project with all its references (NHibernate.dll, Log4Net.dll etc.).

In the second project I face the following problem. There I also use some references that are already in the first project like the Log4Net.dll and of course I added a reference to my helper project because I want to use its functions. When I newly make all references everything is fine but when I compile the second project all references are away. Better to say they are still in the reference folder but in the class files the references are red underlined and VS 2010 Express tells me that the types / namespaces could not be found (missing using directive or assembly reference).

When I delete the references and make new references it works but again when I compile the project the same happens again.

What am I doing wrong?

Answer 1

First thing I'd scheck is the Target Farmework, are you perhaps targetting the first project to a higher version of the framework than the second project? Then try setting the second project to the same target framework as the first one and see if that helps.

Answer 2

I think you first project is targeting the .net 4.0 (full) framework, and the second project is targeting the .net 4.0 client framework.

Alter your second project so it also targets the .net 4.0 (full) framework.