visual studio 2010 - Managed DirectX running from .Net Framework 4.0 app dont hunt

Question

I work on a product that uses Managed DirectX for data visualizations. I was trying to upgrade this product to .net framework 4.0, but I think I'm having issues with Managed DirectX and .Net 4.0 playing together.

The main assembly does not reference managed directX. But when it tries to call into an assembly that does reference managed directX...everthing "halts". Its like the debugger just decided not to step into the assembly. I get no exception, nothing. And when I hit the pause button, the process is sitting on the call into the assembly that references Managed DirectX.

Is there a known compatibility issue with .Net 4.0 and Managed DirectX?

Answer 1

Just in case there is one other shop out there using Managed DirextX with .Net 4.0, if you put the following config entry in your app config, it'll allow you to do it.

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

The problem is that the MDX mixed mode assemblies were compiled against 1.1 runtime, and the way CLR 4.0 loads mixed mode assemblies changed, so this config file entry will allow the CLR 4.0 runtime to use lagacy assembly loading.