Reference a DLL from another DLL

Question

I have a C# application program, let's call it App.exe. It references a DLL named A.dll which in turn references another DLL, namely, B.dll. However the way in which they are referenced is a bit different. In the code of A.dll, it has directly referenced B.dll (by going to Project > References > Add B.dll). However my App.exe has code to load A.dll at runtime using Assembly.Load() etc.

So to recap,

App.exe ---- (runtime loading) ---> A.dll ---- (direct reference) ---> B.dll

All three things (App.exe, A.dll and B.dll) reside in the same directory, let's say ExeDir. Now what I want to do is, put A.dll and B.dll in a sub directory of ExeDir. I can do this by using an App.config file that specify the path of A.dll and asking the App.exe to load A.dll from that path. So far so good.

However the problem is that when I do this, .NET gives me an error saying that it cannot find B.dll which is in the same directory as A.dll. If I move it back to the original directory (the same directory as App.exe) then it works fine. Which means, I can put A.dll in a sub directory, but the B.dll needs to be in the original directory.

Is there any way in which I can keep both DLLs in the sub directory?

Answer 1

Add a <probing> element in your app.config:

http://msdn.microsoft.com/en-us/library/823z9h8w.aspx

<configuration>
   <runtime>
      <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
         <probing privatePath="bin;bin2\subbin;bin3"/>
      </assemblyBinding>
   </runtime>
</configuration>