I've been looking into the CLR profiling interfaces for a project I'm
working on, and I was wondering if it's possible at all to implement them in
C# instead of unmanaged C++?  I'd prefer to work in C# if possible, just for
design reasons, but I'm thinking that it may not be possible to have the
profiler run in the CLR, for technical reasons.  At least, I haven't been
able to get it to work so far.

Here's what I've done:

1) Declared the interface in C#, taken from the IDL file:

[ComImport,
Guid("176FBED1-A55C-4796-98CA-A9DA0EF883E7"),
InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface ICorProfilerCallback
{
   [PreserveSig] int Initialize([In] object pICorProfilerInfoUnk);

   /* ...and the rest of the functions */
}

2) Implement this interface in a class:

[ComVisible(true),
Guid("055FD9E4-195E-4d8b-823F-9AE287803EC8")]
public class ProfilerCallback : ICorProfilerCallback
{
   public int Initialize(object pICorProfilerInfoUnk)
   {
       return 0;
   }

   /* ...and the rest of the functions */
}

3) Register the assembly DLL containing this class with "regasm".  I've
checked the registry afterwards, and my class is properly registered in the
CLSID section.  So far so good.

4) Try to invoke a .NET executable using the profiler:

  ProcessStartInfo si = new ProcessStartInfo(@"D:\someprogram.exe");

  si.EnvironmentVariables.Add("Cor_Enable_Profiling", "1");
  si.EnvironmentVariables.Add("Cor_Profiler",
"{055FD9E4-195E-4d8b-823F-9AE287803EC8}");
  si.UseShellExecute = false;
  Process process = Process.Start(si);

Unfortunately, at this point, the spawned process just crashes with an
access violation--I've put some dumb debugging code inside the
ProfilerCallback constructor and the ICorProfilerCallback.Initialize method,
and neither apparently is getting called by the point it crashes.  I've
tried going through it in the VS.NET debugger and it just hangs badly, so I
can't get anywhere that way.

Is this simply not possible, and I'll have to implement the profiler
interface in C++?  Or have I mucked up the COM interop somewhere, and the
problem has nothing to do with the profiler?

Also, are there any suggestions of a way to get data communicated back and
forth between the process that will be spawning the process to be profiled
(the spawner will be a .NET app), and the profiler callback itself?  I've
been thinking of just using a named memory-mapped file to pass info.

Thanks, any advice would be greatly appreciated.

--
Tony A.