Quick link: To download the wrapper classes click here

While working on a large application targetting the .NET Compact Framework 2.0 I realized that I'll need to feed some native code (specifically, the XSLT processor in MSXML 3.0 SP1) with an IStream implementation.

Articles about interoperating with unmanaged code in the CF are not exactly abundant; to save you the time I spent on incorrect and/or conflicting research, here's the bottom line:

• There is no Managed C/C++ for .NET Compact Framework 2.0. To some this may be old news, but you should really pay attention to this point if you're going to do any serious development against CF. 2.0 adds support for managed COM/ActiveX interop, but otherwise you're completely stuck with P/Invoke.
• Although it's not immediately obvious, CF 2.0 does support exposing managed classes via COM.
• The CF is missing some usually-minor classes from the BCL; in this case I was missing System.Runtime.InteropServices.ComTypes.IStream. Annoying but easy to work around.
• Finally, as an aside, MSXML 3.0 SP1 for Windows Mobile does not support the IXslTemplate and IXslProcessor interfaces, meaning that MSXML 3.0's already lackluster performance in XSLT transformations is further hindered by not being able to cache the interpreted stylesheets. This means that, if you use XSLT, your application will not scale. I was not initially aware of this issue, so I hope our data sets are small enough to handle this, or I may yet come to regret the decision to use XSLT in this project.

I managed to save quite a bit of time by leveraging Oliver Sturm's work, which was originally intended for the desktop. Since the CF is missing a whole bunch of minor classes, the managed definition of IStream included, I originally mucked about with midl trying to generate these definitions from the .IDL files. After this proved to be a genuine chore, I just ripped the definitions straight out of the .NET Framework 2.0 assemblies with the ever-useful Reflector.

You can download the class file here. If you use this it would really be cool if you could drop me an e-mail, and I bet Oliver would be equally appreciative. Enjoy!