Static data in Visual Studio extension

Question

I've got a Visual Studio extension, where much of the functionality is written through MEF. So far, my individual functionality is per ITextBuffer, so I have used the Properties member to cache instances.

However, now I have some functionality that needs to be per-project and per-solution. The EnvDTE classes offer a Properties object but I couldn't figure out whether or not they could store my own arbitrary data. I really don't want to make my own data static.

How can I store per-project and per-solution data without having to resort to global variables?

Edit:

I might also mention that since you can't use MEF imports for static data, even if you hide it in something like a Singleton, then using the global variable route is physically impossible. So I really, really need something that is not a global.

Edit:

I'm talking about object references, not persistent values. I don't need to store anything in a solution or project file, only with the object.

Answer 1

I found a way to convince MEF to honour my static imports, so for now, I'm just using some static data.

(Microsoft.VisualStudio.Shell.Package.GetGlobalService(typeof(SComponentModel)) as IComponentModel).DefaultCompositionService.SatisfyImportsOnce(this);

It was posted somewhere else- maybe even on SO- took me a while to find it though. Note that this has no interface required- reflection is used, so it should be valid for any this.

Answer 2

If I understand your question correctly, you can create a stub class that you do the exports from, instead of trying to force your static classes to export.

public class HostClass
{
   public static string StaticString
   { get  { return "string value"; } }
}

public class HostClassStub
{
   [Export("StaticStringValue", typeof(string))]
   public string StaticString
   { get { return HostClass.StaticString; } }
}

You may also consider just making your static class un-static, if that's an option for you. Remember, that by default MEF imports are singletons, so it should be just like having a global set of variables for each project that does the import.

I know this doesn't address the VS Extensions aspect of your problem, but I haven't dealt with those. Maybe this'll give you a path to your solution, though.