InternalsVisibleTo attribute isn't working

Question

I am trying to use the InternalsVisibleTo assembly attribute to make my internal classes in a .NET class library visible to my unit test project. For some reas

Answer 1

You can use AssemblyHelper tool that will generate InternalsVisibleTo syntax for you. Here's the link to the latest version. Just note that it only works for strongly-named assemblies.

Answer 2

Applies only if you like to keep unsigned assemblies as unsigned assembly (and don't want to sign it for several reasons):

There is still another point: if you compile your base library from VS.Net to a local directory, it may work as expected.

BUT: As soon as you compile your base library to a network drive, security policies apply and the assembly can't be successfully loaded. This again causes VS.NET or the compiler to fail when checking for the PublicKey match.

FINALLY, it's possible to use unsigned assemblies: https://msdn.microsoft.com/en-us/library/bb384966.aspx You must ensure that BOTH assemblies are NOT SIGNED And the Assembly attribute must be without PublicKey information:

<Assembly: InternalsVisibleTo("friend_unsigned_B")>

Answer 3

In addition to all of the above, when everything seems to be correct, but the friend assembly stubbornly refuses to see any internals, reloading the solution or restarting Visual Studio can solve the problem.

Answer 4

I just resolved a similar problem with the InternalsVisibleTo Attribute. Everything seemed right and I couldn't figure out why the internal class I was aiming still wasn't accessible.

Changing the case of the key from upper to lower case fixed the problem.

Answer 5

1- Sign the test project: In Visual Studio go to the properties window of the test project and Sign the assembly by checking the checkbox with the same phrase in the Signing tab.

2- Create a PublicKey for the test project: Open Visual Studio Command Prompt (e.g. Developer Command Prompt for VS 2017). Go to the folder where the .dll file of the test project exists. Create a Public Key via sn.exe:

sn -Tp TestProject.dll

Note that the argument is -Tp, but not -tp.

3- Introduce the PublicKey to the project to be tested: Go to the AssemblyInfo.cs file in the project to be tested and add this line with the PublicKey created in the previous step:

[assembly: InternalsVisibleTo("TestProjectAssemblyName, PublicKey=2066212d128683a85f31645c60719617ba512c0bfdba6791612ed56350368f6cc40a17b4942ff16cda9e760684658fa3f357c137a1005b04cb002400000480000094000000060200000024000052534131000400000100010065fe67a14eb30ffcdd99880e9d725f04e5c720dffc561b23e2953c34db8b7c5d4643f476408ad1b1e28d6bde7d64279b0f51bf0e60be2d383a6c497bf27307447506b746bd2075")]

Don't forget to replace the above PublicKey with yours.

4- Make the private method internal: In the project to be tested change the access modifier of the method to internal.

internal static void DoSomething(){...}

Answer 6

Are you absolutely sure you have the correct public key specified in the attribute? Note that you need to specify the full public key, not just the public key token. It looks something like:

[assembly: InternalsVisibleTo("MyFriendAssembly,
PublicKey=0024000004800000940000000602000000240000525341310004000001000100F73
F4DDC11F0CA6209BC63EFCBBAC3DACB04B612E04FA07F01D919FB5A1579D20283DC12901C8B66
A08FB8A9CB6A5E81989007B3AA43CD7442BED6D21F4D33FB590A46420FB75265C889D536A9519
674440C3C2FB06C5924360243CACD4B641BE574C31A434CE845323395842FAAF106B234C2C140
6E2F553073FF557D2DB6C5")]

It's 320 or so hex digits. Not sure why you need to specify the full public key - possibly with just the public key token that is used in other assembly references it would be easier for someone to spoof the friend assembly's identity.