CODEWITHSUNDEEP
visual-studiodllc++-cli.net-assembly
Greg
Greg

Reputation: 77

Spurious mscorlib of wrong version showing up in dll build

I am building a Cpp/Clr dll with .NET Framework 2.0. Builds fine. However, when I create an Example program to use the dll, also with 2.0, I get this error:

The primary reference "C:\...\MemBuffDll.dll" could not be resolved because it has an indirect dependency on the .NET Framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework.

I have very carefully rebuild the entire solution (not too hard, only two projects in it) and made sure I used only cut and paste of code from one file to another in the re-creation. I as VERY careful to make sure I specified the 2.0 Framework.

When I exclude the Example Solution, everything builds fine. When I reload it, I get the above message. So, I searched in the contents of every file in the entire solution and found the reference in both the .dll and in a file ending with .metagen. The metagen lines of interest are:

ImageRuntimeVersion: v4.0.30319
Assembly MemBuffDll, Version=0.0.*, Culture=Invariant Language (Invariant Country): 
    hash=SHA1, flags=PublicKey
Assembly mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089: 
    hash=None, flags=None
Assembly mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089: 
    hash=None, flags=None
Assembly System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089: 
    hash=None, flags=None

Why are the two lines with 4.0.0.0 in there? This is supposed to be a 2.0 build.

Really puzzled, -greenhorn greg

Upvotes: 1

Views: 1827

Answers (1)

Greg
Greg

Reputation: 77

The answer to the question is:

"The C++ IDE does not support multi-targeting"

Because I didn't understand this answer when I'd seen it in other posts, I'm going to try and clarify for the benefit of other poor souls who stumble upon this "feature".

What this means is that my VS 2010 cannot (correctly) target .net 2.0 when I'm doing a C++ project. I had specified .net framework 2.0 for both of my projects in my solution and the settings were accepted. However, the C++ portion (actually C++/CLI) actually built with two references, both the v2.0 that I had specified and v4.0 that is the native(?) for my VS 2010. Note that it did not throw an error or warning and only the .dll and the .metagen files contained this reference.

When the other project in my solution tried to reference the project, I got the error mentioned in my OP. It would not build.

The solution to the problem is twofold:

  • Install VS 2008 and recreate the problem project under that. Will probably need refactoring. Note that the Express edition worked just fine for this.
  • Change your targets to .net 4.0. This is what I did because refactoring the dll would be a PITA and the target platform (Windows Embedded 8 Standard) supports .net 4.0

Hope this helps somebody else like me that runs into this.

Upvotes: 3

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