CODEWITHSUNDEEP
c#.netvisual-studiodllassemblies
Vortex852456
Vortex852456

Reputation: 739

c# Use dll with different versions in one directory

How can I use different dll's (other Version) with the same name in one directory? For Example, LibA (ExternalLib.dll) has Version 1 and LibB (ExternalLib.dll) has Version 2.

I'm deploying all my programs to the same directory (this is our companys standard and I can't change this fact). The problem is if ProgramB which is using the LibB is deployed in the directory where ProgramA is using the LibA then ProgrammA would not longer work.

For my own Libs I use a Major-Version-Number (.01, .02) if there are big changes. But the Lib I'm using is an external Lib and each version of it requires different licensing-keys (which are handled by the programs itself).

I tried to rename the external libs from "ExternalLib.dll" to "ExternalLib.v1.dll" and "ExternalLib.v2.dll", but when I run my fresh compiled programm it throws an exception that says "ExternalLib.dll could not be found". The reference in my project is set to "ExternalLib.v1.dll" and compilation works fine.

Any ideas / suggestions to handle different assembly versions in the same directory?

Upvotes: 1

Views: 755

Answers (1)

dash
dash

Reputation: 91530

Unfortunately, the filename of the DLL file has very little do do with how .Net is loading these types. The actual name is written into the meta data of the assembly as part of the compilation process. So at runtime, it will be probing for ExternalLib.dll regardless of what you renamed the file to. The usual way to fix this is to install to the GAC and use Strong Naming to reference the specific version.

Given you may not be able to do this, there are 4 things you could try:

  1. Ask the vendor to produce version specific DLL's for you. They could compile such that the version name is part of the filename and included in the assembly manifest. This would be the simplest solution for you.

  2. Handle the AssemblyResolve event and manually try and use Assembly.Load to point at the file you want such that you can specify specifically which dll to use. See http://support.microsoft.com/kb/837908 for more information, but effectively you'll be using Assembly.LoadFrom(specific_path) to choose the file where the code will load from.

  3. If possible, you might also be able to use ildasm.exe to decompile the dll's to Intermediate Language (IL), then use ilasm.exe to recompile it to a new dll name. You would then reference this new DLL name in your project.

  4. If the assembly is not signed, then you may be able to edit the manifest yourself; you can either use a compatible binary editor or possibly MT.exe.

Upvotes: 4

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