.net - Is it possible to replace a reference to a strongly-named assembly with a "weak" reference?

Question

I'm writing a .NET tool that requires the SQL Server SMO library. I don't care if it's the version from Server 2005 (9.0), 2008 (10.0) or 2008 R2 (probably 10.5, didn't check). The SMO library is installed together SQL Server, so I can safely assume that on any system with SQL Server installed, some version of the SMO library is available as well.

Unfortunately, the SMO libraries are strongly-named: If I add a reference to SMO 9.0 in my project, it will fail (FileNotFoundException) if only SMO 10.0 is present on the customer's system, and vice versa.

Is there some way to tell the compiler that any version of the library is fine for me? Or do I really have to distribute 3 identical versions of my tool, each compiled to a different version of the SMO?

---

Disclaimer: I do know that the SMO libraries (and the libraries required by the SMO libraries) can be redistributed. But there's a big difference between (a) one slim 100KB standalone EXE and (b) a full-blown setup package that installs a whole bunch of prerequisites.

Disclaimer 2: I am aware of the following duplicates:

• c# - can you make a “weak” assembly reference to a strong named assembly
• Need a C# Assembly to reference a strongly named assembly loosely

The solutions provided do not fit, however. In question 1, the developer has control over the referenced DLL (which I do not); in question 2, the developer has control over the target systems (which I do not either).

Answer 1

You can use Assembly Binding Redirection.

For example:

 <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Telerik.Web.UI" publicKeyToken="121fae78165ba" />
        <bindingRedirect
               oldVersion="2010.0.0.1"
               newVersion="2011.1.315.40" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

Update

I see from your comment that we have to think about this in reverse a little.

A very promising approach, but, unfortunately, it merely replaces the dependency on version X with a (strong) dependency on version Y. I still have a dependency on one particular version.

I did some experiments where I compiled against a version of an assembly: 4.0.0.0, but wanted to make sure it would load that version, plus some selected older versions. In this way you are not dependent on any single version but against any of the versions you have configured.

The following will ensure that VersionedAssembly will be loaded if any of the following versions are on the system: 4.0.0.0, 3.0.0.0, 2.0.0.0, 1.0.0.0.

   <runtime>
      <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
         <dependentAssembly>
            <assemblyIdentity name="VersionedAssembly" publicKeyToken="20d85e" />
            <bindingRedirect oldVersion="4.0.0.0" newVersion="1.0.0.0"/>
         </dependentAssembly>
         <dependentAssembly>
            <assemblyIdentity name="VersionedAssembly" publicKeyToken="20d84e" />
            <bindingRedirect oldVersion="4.0.0.0" newVersion="2.0.0.0"/>
         </dependentAssembly>
         <dependentAssembly>
            <assemblyIdentity name="VersionedAssembly" publicKeyToken="20d84e" />
            <bindingRedirect oldVersion="4.0.0.0" newVersion="3.0.0.0"/>
         </dependentAssembly>
      </assemblyBinding>
   </runtime>