Question

I am trying to access a VB.NET DLL (.NET FX 4.0) from a VB6 client in a reg-free scenario.

I tried to follow the example from http://msdn.microsoft.com/en-us/library/ms973915.aspx, but with no success. I downloaded (link in the article) the sources and compiled, no success (error message: Run-time error ‘-2146234341 (8013101b)’: Automation error”). Running from VB6 IDE using registered VB.NET DLL works.

I tried other examples where the .NET DLL is created as a COM Class (using “COM Class” template from VS2010), with manifest for referenced DLL embedded or not, but nothing worked for me.

Can somebody provide some simple source code with manifests example of VB.NET DLL (.NET FX v4) used in VB6 client in reg-free scenario?

Thanks much in advance.

Answer 1

Run-time error ‘-2146234341 (8013101b)’: Automation error

Your problem doesn’t have anything to do with a manifest, you’ll need to fix this one first. The error code is COR_E_NEWER_RUNTIME. In other words, your [ComVisible] class cannot be loaded because it depends on CLR version 4. And the program has already loaded the CLR, version 2 most likely, because another [ComVisible] class asked first. And it asked for version 2.

You’ll need an app.exe.config file that forces CLR version 4 to get loaded, even when somebody asks for version 2. It should look like this:

<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0"/>
  </startup>
</configuration>

Give it the same name as the vb6 exe (like “foo.exe.config” to match “foo.exe”) and put it in the same directory as the .exe. If you want to use the VB6 IDE to debug your vb6 code that uses this library then you also need vb6.exe.config in c:\program files\microsoft visual studio\vb98