Can I use Injection / IoC Dependency for ASP.NET MVC FilterAttribute?
I have a simple custom FilterAttribute
one that I use to decorate various ActionMethods
.
eg.
[AcceptVerbs(HttpVerbs.Get)]
[MyCustomFilter]
public ActionResult Bar(...)
{ ... }
Now I want to add some entries to this CustomFilter action. So being a good boy, I use DI/IoC
... and as such want to use this template for my custom one FilterAttribute
.
So, if I have the following ...
ILoggingService
and want to add this custom one FilterAttribute
. I'm not sure how to do this. For example, I find it easy to do the following ...
public class MyCustomFilterAttribute : FilterAttribute
{
public MyCustomFilterAttribute(ILoggingService loggingService)
{ ... }
}
But compiler errors describing the attribute that decorates mine ActionMethod
(mentioned above ...) requires 1 argument . So I'm just not sure what to do :(
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I have property injection working with Ninject and Ninject.Web.MVC .
As long as you have a factory controller from Ninject.Web.MVC it's pretty simple.
eg.
public class EventExistsAttribute : FilterAttribute, IActionFilter
{
[Inject]
public IEventRepository EventRepo { private get; set; }
public void OnActionExecuting(ActionExecutingContext filterContext)
{
//Do stuff
}
public void OnActionExecuted(ActionExecutedContext filterContext)
{
//Do something else if you so wish...
}
}
This has a disadvantage, essentially having a "hidden" dependency, so to speak ... but there is little that can be done about it.
HTHS,
Charles
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Yes it is possible to use dependency injection in FilterAttribute. However, it is not possible to use the constructor injector in the FilterAttribute. This is not a limitation of ASP.NET MVC, it is common to all .NET code, as the values passed to the constuctor attribute are limited to simple types .
[MyFilter(ILogger logger)] // this will not compile
public ActionResult Index()
{
return View();
}
Thus, a common practice is to make the dependency dependent on your filter, as in @Charlino's example. Then you can use property injection. You can use Ninject to decorate a filter property like @Charlino's example. Or, as @mrydengren suggested, you can do it in a custom subclass of ControllerActionInvoker.
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