如何在 dotnet 控制台应用程序中引用和使用同一程序集的多个版本？

Question

Lets say i have the below assembly files reference in my solution:

1. a.dll
2. b.dll
3. c.dll
4. Main_43.dll
5. a_40.dll
6. b_40.dll
7. c_40.dll
8. Main_40.dll

My console application used to load only the first 4 before as the client used Main_43.dll which internally used a,b and c dll files. Now, i have to add a new client to my console application that will be using Main_40.dll which is the older version of Main_43.dll(I have to use the old version. No option to upgrade). I have renamed a, b and c dll files for this version by suffixing '_40' as seen above.

I have referenced all of them in my console application. How can i tell the application to use Main_43 or Main_40 based on the parameter i pass to console app and how can i be sure that Main_40 will reference a,b and c dlls files that are meant for v40 and vice versa?

Also, what is the best practice to call methods in my program that might me in both dlls? Should i use the full reference name such as:

Main_40.Export exportData = new Main_40.Export(); 

or is there a better way?

The assembly files are strong named

Answer 1

So this is how i went about with the change. I created a folder 'libs' under which i have 2 folders v40 and v43 and i have put the dlls 1 to 4 in v43 and the rest in v40 and then when my class is called, i load the dll dynamically. I also made sure that 'Copy always' is set so that dlls are always moved to the folder during build.

Now when i hit the client constructor that will be using v40 dll, i load the assembly path and then create an instance of main_40

    protected const string mxMainDLLPath = @"libs\v40\Main_40.dll";
    dynamic mainObj = null;
    public ClientClass()
    {
        Assembly assembly = Assembly.LoadFrom(mxMainDLLPath );
        Type T = assembly.GetType("Main_40.Export");
        mainObj = Activator.CreateInstance(T);
    }

Now to call any method in Main_40.dll, i can do mainObj.Export().

Thanks to @NightOwl888 for all the help.