在 Windows / C# 中卸载 DLL

Question

I have a piece of hardware, for which the maker provides a DLL and an example Visual Studio project.

I wrote a tool based on this project, using the newest version of the DLL, and it runs fine.

Now, there are also other (older) tools, using other versions of the DLL. Those tools run fine as well, on their own.

The problem occours when I run both tools (after another, not simoultaneously!) without rebooting Windows in between.

Then I get an "Version mismatch" error. I suspect that Windows still keeps the DLL loaded, although the program that ran first terminated correctly.

Since I do not have access to the source code of the "other tools", is there any way to

1. enforce reloading of the DLL with the correct version when my program starts and;
2. Force Windows to unload the DLL when my program exits

so there won't be any problems?

Answer 1

Since you don't have the source code of these other tools, you will have to create a manifest file for each application that you want to use that's using a version of this dll. This is going to be a file with the same name as the executable, with the ".manifest" extension. You can find more about application manifests here:

https://msdn.microsoft.com/en-us/library/windows/desktop/aa374191%28v=vs.85%29.aspx

Once you have the manifest file in place, you would specify the exact dll it needs to load with something like:

  <dependency>
    <dependentAssembly>
      <assemblyIdentity type="win32" 
                        name="Proseware.Research.SampleAssembly" 
                        version="6.0.0.0" 
                        processorArchitecture="X86" 
                        publicKeyToken="0000000000000000" 
                        language="*"
      />
    </dependentAssembly>
  </dependency>