Using MEF with exporting project that uses resources (xml) contained in the xap.

Question

I'm doing a proof of concept app in SL4 using MEF and as part of the app I am importing another xap from an existing Silverlight Project and displaying it in my host project.

The problem is that the existing app uses some .xml files (as content) and it uses linq2xml to load these files which are (assumed to be) bundled in the xap.

When I compose the application the initalization fails because the host app doesn't contain the xml files. If I copy these xml files into the host project and run it the composition works fine. However, I need to keep the xml files in the original project.

Is there a way that I can download a xap and look at it's contents for xml files and then load them into the host xap at runtime so that after the compostion takes place the xml resources that are required can be found?

Or should I work out some kind of contract with an import/export to pass the xml files to the host xap?

As the people developing the imported xaps (should the project go ahead) are from a different company, I would like to keep changes to the way they develop their apps to a minimum.

Answer 1

I assume you are using the DeploymentCatalog to download the second xap? Unfortunately there's no way to get at resources included in that xap. You could have the resources embedded in assemblies which are included in the xap, and then modify the way they are loaded.

If you really don't want to change the way the secondary xap is structured, you might be able to write your own DeploymentCatalog which would also allow you to load resources from the downloaded xap. The source code to DeploymentCatalog is available, so you could base it off of that.

Answer 2

I've managed to find a solution that I'm fairly happy with.

Instead of building the .xml files as 'content' to go within the xap, I have built them as 'resource' then used Application.ResourceStream() and loaded the xml using a stream.

It means the second xap developers will have to change the way they operate, but its only one extra line of code and changing the Build Action, I'm sure they can handle.