Question

I have a project which has a set of binary dependencies (assembly dlls for which I do no have the source code). At runtime those dependencies are required pre-installed on the machine and at compile time they are required in the source tree, e,g in a lib folder.
As I’m also making source code available for this program I would like to enable a simple download and build experience for it. Unfortunately I cannot redistribute the dlls, and that complicates things, since VS wont link the project without access to the referenced dlls.

Is there anyway to enable this project to be built and linked in absence of the real referenced dlls?

Maybe theres a way to tell VS to link against an auto generated stub of the dll, so that it can rebuild without the original? Maybe there’s a third party tool that will do this? Any clues or best practices at all in this area?

I realize the person must have access to the dlls to run the code, so it makes sense that he could add them to the build process, but I’m just trying to save them the pain of collecting all the dlls and placing them in the lib folder manually.

Answer 1

Maybe one of these ideas will help you to solve the problem:

• Derive interfaces from all classes in the 3rd party dlls. Put these interfaces into an own project (same solution) and add a reference to this interface assembly. Also add an EventHandler to AppDomain.AssemblyResolve and try to find and load the assemblies at run-time. (Credits go to NG)
  • Depending on how big the dlls are and how often changes are made to the public part this can get a real pain.
• Provide a readme.txt where you explain how to get the needed assemblies and where the user should put them relative to the project path. Normally VS is smart enough to remove the exclamation mark right after you put the assembly into the right spot, where the project references it from (maybe you have to press refresh in Solution Explorer) (Credits go to Paul)
  • Don’t forget to add the readme.txt also to your solution by right clicking on your solution and select ‘Add -> Existing Item’. In this case it will get a quite prominent place within visual studio Solution Explorer and the user can read it on a double click.
• Create another project within your solution that is able to download all the needed dlls automatically and to put them into the right spot. Maybe it should check beforehand if these needed files are already there before it starts to download. Set the Project Dependencies of your original project, so that it will depend on this one. So it will always be built before your original one. Then start this download helper tool in the pre-build event of your original project and don’t forget to exit your program with an int value. 0 means success, any other error and so also Visual Studio knows if your tool was successfull and stops the compile process before hanging on missing dlls.
  • Maybe it is nearly impossible to automatically download the files, cause you need a login to a webpage or some cookies, flash, captcha, etc. is used which can’t be automated by a tool.