MVC 3 ninject bind lazy evaluated parameter

Question

I want o bind my controller with a parameter that is lazy evaluated.

 protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        try
        {
            return controllerType == null
                       ? null
                       : (IController) _ninjectKernel.Get(controllerType);
        }
        catch (Exception ex)
        {
            throw;
        }
    }

And I have the next binding:

_ninjectKernel.Bind<IFilesRepository>().To<FilesManager>().WithConstructorArgument("storageFolderAbsolutePath", c => c.ToString());

The problem is at the lambda function. I want to return Server.MapPath("/") ... but I don't have the request context in the c object. How can I sent it?

Answer 1

I'm not overly familiar with Ninject, but you should be able to register a provider with the container to be able to resolve a HttpContextBase. By doing so, the IFilesRepository can now take a HttpContextBase as a constructor argument, which will be injected by the container, using the provider, when creating an instance of IFilesRepository.

To register a provider (using a delegate to resolve the service),

Bind<HttpContextBase>().ToMethod(context => new HttpContextWrapper(HttpContext.Current));

Be aware however, that the life style of an IFilesRepository would most likely need to change to a "per Web Request" lifestyle, as the HttpContext.Current is created per web request, so you wouldn't want to go holding onto that in an IFilesRepository that had a longer life style. You may want to abstract out the "mapping paths" functionality so that you can have an IFilesRepository with a longer lifestyle.

Answer 2

Since the server variable is related to the current HttpContext you will have to retrieve it inside the FilesManager class (using a separate Interface for that purpose if you will )