ASP.NET MVC 3 Dependency Injection - Controllers, Views & Action Filters

问题

I'm trying to get dependency injection working in an ASP.NET MVC 3 application using Microsoft Unity. First i have implemented my own IDependencyResolver and activated it in my Global.asax file like so:

DependencyResolver.SetResolver(new UnityDependencyResolver(container));

I found that i don't need to do anything else to get controller injection (via both the constructor and [Dependency] attribute) to work. With the default view engine i also found i could get the [Dependency] attribute to work in the standard views but not the Layout views. Is it possible to get this to work for the Layout Views aswell?

However i have implemented my own view engine which inherits from VirtualPathProviderViewEngine that overrides the CreateView/CreatePartialView methods and returns my own custom view (implements IView). See the Render method of the custom view below:

public void Render(ViewContext viewContext, TextWriter writer) {
    var webViewPage = DependencyResolver.Current.GetService(_type) as WebViewPage;
    //var webViewPage = Activator.CreateInstance(_type) as WebViewPage;

    if (webViewPage == null)
        throw new InvalidOperationException("Invalid view type");

    webViewPage.VirtualPath = _virtualPath;
    webViewPage.ViewContext = viewContext;
    webViewPage.ViewData = viewContext.ViewData;
    webViewPage.InitHelpers();

    WebPageRenderingBase startPage = null;

    if (_runViewStartPages)
        startPage = StartPage.GetStartPage(webViewPage, "_ViewStart", _viewStartFileExtensions);

    var pageContext = new WebPageContext(viewContext.HttpContext, webViewPage, null);
    webViewPage.ExecutePageHierarchy(pageContext, writer, startPage);
}

With the commented out line i completely lost dependency injection within my views so i changed it to the line above which again works fine for the standard views but not for the Layout views. I'd appreciate it if you could show me how the above could be modified to work for the Layout views aswell?

Finally i'm trying to get action filter injection working aswell. I have found two different cases:

1. Apply the filter to the action via an attribute.

2. Defining it as a global filter, e.g.:

   GlobalFilters.Filters.Add(new TestAttribute());

Neither seem to use the dependency resolver. Therefore i need to do some extra work. Please correct me if there's a better way. To enable the first scenario i did the following:

public class UnityFilterAttributeFilterProvider : FilterAttributeFilterProvider {
    private IUnityContainer _container;

    protected override IEnumerable<FilterAttribute> GetControllerAttributes(ControllerContext controllerContext, ActionDescriptor actionDescriptor) {
        var attributes = base.GetControllerAttributes(controllerContext, actionDescriptor);

        foreach (var attribute in attributes) {
            _container.BuildUp(attribute.GetType(), attribute);
        }

        return attributes;
    }

    protected override IEnumerable<FilterAttribute> GetActionAttributes(ControllerContext controllerContext, ActionDescriptor actionDescriptor) {
        var attributes = base.GetActionAttributes(controllerContext, actionDescriptor);

        foreach (var attribute in attributes) {
            _container.BuildUp(attribute.GetType(), attribute);
        }

        return attributes;
    }
}

And then defined this within my Global.asax file like so:

FilterProviders.Providers.Remove(FilterProviders.Providers.Single(f => f is FilterAttributeFilterProvider));
FilterProviders.Providers.Add(new UnityFilterAttributeFilterProvider(container));

This works fine but i was wondering if this is the correct way to do it? To resolve the second case i simply changed where i defined my global filter to the following:

GlobalFilters.Filters.Add(DependencyResolver.Current.GetService<TestAttribute>());

This again now works but is this the correct way to do it?

I'd appreciate the help. Thanks

来源：https://stackoverflow.com/questions/10813291/asp-net-mvc-3-dependency-injection-controllers-views-action-filters