Can you have both c# and visual basic in the same web site project?

Definitely! It simply wouldn’t make sense from a new project standpoint, code reviews, coding standards, continuity, project maintenance, etc.

however, people still want it.  to-date i never really tried (and that’s been my answer).  i was presented with a usable scenario of why you may need (not want, need) to do this, so i finally tried it.  the answer: yes…kinda…sometimes.

let’s assume we have a web site structure like this:

we have the App_Code folder and a .cs and a .vb file in the same projects (separated into sub-folders).  note that the project sees them as folders (yellow folder icon) in the special folder.  each class within there basically has a “hello world” function only, like this in the c# file:


public string SayHelloCS()
    {
      return "Hello from CS";
  }
and the visual basic file has a similar function emitting "Hello from VB."

now, if you run default.aspx in this structure, this is what you will see:

The files ‘/WebSite5/App_Code/VBCode/Class2.vb’ and ‘/WebSite5/App_Code/CSCode/Class1.cs’ use a different language, which is not allowed since they need to be compiled together.

interesting?  probably not, but it makes sense…so how do we overcome.  we use a configuration option called .  here’s what we need to add to our <compilation> node in our web.config:

<compilation debug="false">
          <codeSubDirectories>
            <add directoryName="VBCode"/>
            <add directoryName="CSCode"/>
          </codeSubDirectories>
       </compilation>

once we add those codeSubDirectory nodes, let’s “look” at what the project structure looks like now:

as you can see the code folders are now “special” in the eyes of visual studio.  now if we browse default.aspx we will see:

Hello world from CS. Hello world from VB