Create Silverlight Assembly having C/C++ Reference

Currently I'm trying to compile a C/C++ library for S开发者_高级运维ilverlight Project in order to re-use a c-based codec - FFMpeg, within the silverlight In-Browser Application.

Approaches Tried :

1) Try to include a C++ Class within Silverlight DLL project by declaring c function which is exported in dll as - __declspec(dllexport)

The compilation works but when I tried to reference the C method from within Silverlight Project results in the Native call outside CLR issue.

url ref. - http://social.msdn.microsoft.com/Forums/en-US/clr/thread/339afacb-c9f2-46a4-9feb-8df793a65155

So I've realized after further reading that the silverlight error is becuase of the CLR being able to allow Managed Assemblies only and not Native Code.

Conclusion : One cannot include C++/C code directly within silverlight dll.

2) Next, I've been trying to create a C++ based Managed Assembly with the goal to incorporate a simple C++ class / C function within a Silverlight Managed Assembly.

Steps -

1. Create a C++ CLR Class Lib project providing a managed assembly
2. Create a C#/.Net Wrapper Class Lib project which calls the C++ CLR Lib which is also a managed assembly
3. Convert the C#/.Net managed assembly Wrapper dll into a silverlight managed assembly dll
4. Consume the silverlight dll within a silverlight application

url ref. - http://www.netfxharmonics.com/2008/12/Reusing-NET-Assemblies-in-Silverlight

Conclusion : Not sure about the possiblility since I'm still trying get success with the conversion steps which is a bit complex to follow.

Is there a tested approach to be able to re-use C code within Silverlight Lib ?

TIA, Anthony

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Basically you want to access a COM Interop assembly from Silverlight.

This is only possible in a trusted application (http://msdn.microsoft.com/en-us/library/ee721083(v=vs.95).aspx)

Trusted applications in SL 4 are only allowed in OOB apps, if you want to use a COM Interop assembly from a Web application in Silverlight you'll have to use SL5.

Here's a bit of extra info on how to use COM Interop from a trusted application:

http://www.uxmagic.com/blog/post/2010/03/09/COM-InterOp-for-Trusted-Applications-in-Silverlight.aspx

Hope this helps you.

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In Silverlight 4 you can only access native code via COM interop. It doesn't help to wrap the native code in a mixed-mode (C++/CLI) assembly.

The next version of Silverlight will allow you to access native code via P/Invoke. Don't know if it will support mixed-mode assemblies.

Your current options are:

1. Create a COM wrapper for your library
2. Wait for Silverlight 5 and use P/Invoke

AFAIK both solutions will require the native code libraries to be installed on the clients before starting the silverlight app.