Can I use two incompatible versions of the same DLL in the same process?

Question

I\'m using two commercial libraries that are produced by the same vendor, called VendorLibA and VendorLibB. The libraries are distributed as many DLLs that depend on the com

Answer 1

It is actually possible to implicitly load different versions of a dll into a single process.

Doing this entails:

1. Creating two assemblies, each containing a version of the dll that must be loaded multiple times. Sounds complicated but practically it entails little more than creating (2) named sub folders, each with a .manifest file containing some xml, and its own copy of the dll. So, VendorUtilsAssemblyV1 and VendorUtilsAssemblyV2

2. Making each dependent dll use the assembly mechanism to resolve the implicit dependency - by adding a assemblyDependency directive that explicitly identifies VendorUtilsAssemblyV1 or V2.

There are some options for point 2. If the VendorLibA and VendorLibB files do not contain their own manifests, then you can simply add manifest files with the required dependentAssembly directive named VendorLibA.2.dll.manifest and VendorLibB.2.dll.manifest. If they already contain manifests (probably to link to the VS2005 or VS2008 C-Runtime) then use the MT.EXE tool to merge in the new dependency.