The best way to import a collection of values in a controller using MEF

I have an ASP.NET MVC2 application that supports visualization plug-ins/providers. The IVisualization interface is defined in a common assembly which is referenced by both the ASP.NET MVC2 app, and any visualization providers.

In the Visualization controller, I have a method which returns all the applicable visualizations for a given set of data. In order to scan the available providers, I use the following code in the controller's ActionMethod.

var catalog = new DirectoryCatalog(HttpRuntime.BinDirectory); 
var container = new CompositionContainer(开发者_高级运维catalog);
var visualizations = container.GetExportedValues<IVisualization>();

However, I feel like if I have the following in the controller

[ImportMany]
public IEnumerable<IVisualization> Visualizations { get; set; }

then the import should happen automatically. What am I missing that prevents the automatic imports?

Also, is the code that I am currently using going to kill scaling of website?

Thanks, Erick

In order for MEF to satisfy the imports, it needs to also be responsible for the instantiation of the controller. You can do that in MVC by using a custom controller factory. You can find a sample (maybe outdated) of this in my blog: Link

If you have a controller that declares that particular property import, you must programatically call one of MEF's methods to satisfy them.

Some options are:

container.GetExportedValues<MyController();
container.ComposeParts(controllerInstance);

among others.

I hope this illustrates my point.