Access Viewbag property on all views - asp.net

How can I access some ViewBag properties across all my views? I want to have some information like current user name, etc accessible everywhere, but without having to to specifically define the properties in each ActionResult method on my project

The best and straight forward way to accomplish your requirement is to make a Custom Base Controller and inherit your Controller from this Base Controller.
public class MyBaseController : Controller
{
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
ViewBag.someThing = "someThing"; //Add whatever
base.OnActionExecuting(filterContext);
}
}
Now instead of inheriting Controller class,inherit MyBaseController in your Controller as shown :-
public class MyOtherController : MyBaseController
{
public ActionResult MyOtherAction()
{
//Your Stuff
return View();
}
//Other ActionResults
}

You can achieve what you want in a number of ways, each one with their pros and cons.
1. With a Base Class
public class BaseController : Controller
{
protected override ViewResult View(IView view, object model)
{
this.ViewBag.MyProperty = "value";
return base.View(view, model);
}
}
PROS: Quite simple to implement, few lines of code, highly reusable, can be opted-out at will (see comments below).
CONS: Being forced to derive all your controllers from a base class might have some impact, especially if you have a lot of controllers already in place and/or you need to derive them from other base classes.
2. With a Module
public class ViewBagPropertyModule: Module
{
protected override void AttachToComponentRegistration(IComponentRegistry cr,
IComponentRegistration reg)
{
Type limitType = reg.Activator.LimitType;
if (typeof(Controller).IsAssignableFrom(limitType))
{
registration.Activated += (s, e) =>
{
dynamic viewBag = ((Controller)e.Instance).ViewBag;
viewBag.MyProperty= "value";
};
}
}
}
PROS: None I’m aware of.
CONS: None I’m aware of (except being a bit counterintuitive).
3. With a RegisterController Hook
builder.RegisterControllers(asm)
.OnActivated(e => {
dynamic viewBag = ((Controller)e.Instance).ViewBag;
viewBag.MyProperty = "value";
});
PROS: Fast, secure, reusable: ideal for any IoC design pattern.
CONS: Not always suited for small project and/or simple websites: if you’re not using IoC you’re often not using RegisterController at all.
4. With an ActionFilter attribute
public class MyPropertyActionFilter : ActionFilterAttribute
{
public override void OnResultExecuting(ResultExecutingContext filterContext)
{
filterContext.Controller.ViewBag.MyProperty = "value";
}
}
and then in your Global.asax.cs file:
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
GlobalFilters.Filters.Add(new MyPropertyActionFilter(), 0);
}
PROS: Easily the less-obtrusive method amongst those mentioned.
CONS: None I’m aware of.
I also wrote this article on my blog explaining all the above methods.

One way: Create a custom attribute, then you can apply it globally in the FilterConfig. Then you don't have to do anything in your controllers.
public class MyCustomViewActionFilter : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
dynamic ViewBag = filterContext.Controller.ViewBag;
ViewBag.Id = "123";
ViewBag.Name = "Bob";
}
}
In App_Start/FilterConfig.cs:
public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
filters.Add(new MyCustomViewActionFilter());
}
Another way if all you need is the User information. You can add the following to the top of your view:
#using Microsoft.AspNet.Identity
Then access your User Name using the following syntax:
#User.Identity.GetUserName()
You can also override the IPrincipal implementation and provide your own properties and methods to add more information you need to render.
UPDATE: looking at MVC 6 in Asp.Net vNext this is actually baked into the framework. http://www.asp.net/vnext/overview/aspnet-vnext/vc#inj

My current solution:
Create a base controller with all needed properties (very useful and advisable).
public abstract class BaseController : Controller {
public string MyProperty { get; set; }
}
Inherits all your controllers, from the base controller.
public class MyController : BaseController {
//you can read your property here
}
In your views, add this line just after the "#model" sentence:
#{ BaseController ctr = ViewContext.Controller as BaseController; }
Now, you can use the property in your view, without populate the ViewBag, without the need of check and cast the ViewBag values, etc.
In the view, you can use an simple inline expression:
#(ctr.MyProperty)
Or do some magic logic...
#{
if(ctr.MyProperty == "whatelse") {
//do ...
}
}
Easy, fast and comfortable.

For Net Core 5 Mvc app:
Create a ActionFilter class first:
public class GlobalSettingFilter : IActionFilter
{
private IConfiguration configuration;
//For example will get data from the configuration object
public GlobalSettingFilter(IConfiguration configuration)
{
this.configuration = configuration;
}
public void OnActionExecuting(ActionExecutingContext context)
{
//Populate the ViewData or ViewBag from your data source
(context.Controller as Controller).ViewData["helpUrl"] = configuration.GetValue<String>("helpUrl");
}
public void OnActionExecuted(ActionExecutedContext context){}
}
Then, on Startup add:
public void ConfigureServices(IServiceCollection services)
{
...
services.AddControllersWithViews(options =>
{
options.Filters.Add(new GlobalSettingFilter(Configuration));
});
}
Just for the sake of completeness, to get the configuration object use:
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
...
}

You can create a base controller that is inherited by all of your controllers, and in this controller (the base one) add:
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
// Fill your global viewbag variables here
}

Related

any work around to allow for an action result to accept a Abstract class as parameter

I have different configurations all inheriting from a base configuration that are customized in forms. I want all of these to be handled by a single action result.
[HttpPost]
public IActionResult Register(AbstractBaseConfig config)
{
...do some logic...
return View("../Home/Index");
}
However, this is not possible because you cannot base in abstract classes as a parameter to an action result. Is there any work around for this so I don't need a seperate action result for each configuration? (I still want each configuration to be it's own class, I only need access to the base class methods in the action result logic).
Basically you can't, and the reason is that MVC will try to do new AbstractBaseConfig() as part of the Data Binding process (which parses the URL or the Form Post and puts the results in a concrete object). And by definition, doing new AbstractBaseConfig() is impossible for an abstract class.
It also makes sense for other reasons, I will explain why.
You seem to expect that MVC can determine the class from the parameters that are being passed in. That is not how it works, in fact the opposite is true: the Action Method has to specify the exact class, and then the Binder will instantiate that exact class and try to bind its properties.
Suppose you had this:
public abstract class Thing { public int ID { get;set; } }
public class NamedThing : Thing { public string Name { get;set; } }
public class OtherThing : Thing { public string Name { get;set; } }
and suppose it would be allowed to use:
public IActionResult Register(Thing thing)
then what would you expect to be in thing after Data Binding: a Thing object with only the ID set? Or one of the other object types, with Name set, but how would MVC ever be able to know which class you meant?
So for all these reasons, this is not possible.
You could have a base class inherit the abstract class and all your classes inherit from that base class whilst having that base class as your parameter
Take for example
public abstract class ABase
{
public void stuff()
{
var stuff = string.Empty;
stuff = "hello";
}
public virtual void otherstuff()
{
var stuff = string.Empty;
stuff = "hello";
}
}
public class Base : ABase
{
//empty
}
public class Derived : Base
{
public void mystuff()
{
this.stuff();
}
public override void otherstuff()
{
// Custom code
}
}
public ActionResult Register(Base config)
{
}

How to create a BaseController with a ViewBag

I need to do the following:
I have some Controllers ready and running, but now I want to create a BaseController.
Each of my Controllers should inherit from it like this:
public class MySecondController : BaseController
thats already running so far. Now the Problem:
I want to add a ViewBag into this base controller. This ViewBag should be accessable from every view which is called in my controllers.
How to realise this?
You can override OnActionExecuting method in the overridden method you can data to ViewBag dictionary.
public abstract class BaseController : Controller
{
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
ViewBag.someThing = "someThing"; //Add whatever
base.OnActionExecuting(filterContext);
}
}
Updated for .net Core 2019:
using Microsoft.AspNetCore.Mvc.Filters;
public abstract class BaseController : Controller
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
ViewBag.someThing = "someThing"; //Add whatever
ViewData["someThingElse"] = "this works too";
TempData["anotherThing"] = "as does this";
base.OnActionExecuting(filterContext);
}
}

MVC custom filter, invoke ASP.NET pipeline event manually for unit test

public abstract class MyControllerBase : Controller
{
protected override void OnActionExecuting(ActionExecutingContext context)
{
// do some magic
}
}
All of my controllers inherit from MyControllerBase. The problem is that now I can't unit test certain methods because the filter sets some authorisation/logic flags which influence code path.
Is there any way to manually trigger OnActionExecuting? How does the pipeline trigger these events?
EDIT: to show a little more the idea behind this design in response to comments. I basically have something like this:
public abstract class MyControllerBase : Controller
{
protected override void OnActionExecuting(ActionExecutingContext context)
{
UserProperties =
_userService
.GetUserProperties(filterContext.HttpContext.User.Identity.Name);
ViewBag.UserProperties = UserProperties;
}
public UserProperties { get; private set; }
public bool CheckSomethingAboutUser()
{
return UserProperties != null
&& UserProperties.IsAuthorisedToPerformThisAction;
}
// ... etc, other methods for querying UserProperties
}
So now anywhere in View or Controller I can get details of the current user, what is their email, what authorisation they have, which department they work for etc.
Example:
public class PurchasingController : MyControllerBase
{
public ActionResult RaisePurchaseOrder(Item item)
{
// can use UserProperties from base class to determine correct action...
if (UserProperties.CanRaiseOrders)
if (UserProperties.Department == item.AllocatedDepartment)
}
}
So this design works really nice, but as you can see testing the above action is difficult as I can't directly manipulate the UserProperties in the test set up.
I'm not sure you're suppose to override OnActionExecuting like that in MCV, normally I make an ActionFilterAttribute
public class SomeMagicAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
}
}
Then your class:
[SomeMagic]
public abstract class MyControllerBase : Controller
{
}
Then in your unit test you can just do
var magic = new SomeMagicAttribute();
var simulatedContext = new ActionExecutingContext();
magic.OnActionExecuting(simulatedContext);

ASP.NET MVC - Unit Testing Override Initialize Method

I've got an abstract class shown below which gets inherited by all the other controllers. Is it possible to test this method at all? Btw, I'm trying to use MOQ but no luck. If you could help me will be much appreciated:
public abstract class ApplicationController : Controller
{
protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
base.Initialize(requestContext);
//do some stuff here
}
}
If you take a look at the source code of base Initialize method you will find out that what it does is that it sets up ControllerContext and url stuff. Now, download MvcContrib TestHelper and check out TestControllerBuilder . The builder sets up everything you need in order to have controller context and other stuff which you depend upon.
Ok, we are not over yet - you wanted to test your own override of Initialize right?
TestControllerBuilder doesnt call your Initialize because it does initialization in different way. I suggest you to factor out your custom Initialize() logic out into different method. Then create fake (stub) subclass with public method that calls this factored out protected Initialize. Are you with me?
something like:
public abstract class ApplicationController : Controller
{
protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
base.Initialize(requestContext);
MyInitialzie()
}
protected void MyInitialize()
{
ControllerContext.XXX // do whatewer you want here. Context is already setted up
}
}
class FakeController: ApplicationController
{
public void CallMyInitialize()
{
MyInitialize();
}
}
Later in test class:
[Test]
public void MyInitializeTest()
{
TestControllerBuilder builder = new TestControllerBuilder();
FakeController controller = new FakeController();
builder.InitializeController(controller);
controller.CallMyInitialize();
//TODO: verification of MyInitialize assumptions
}
Is that clear?

Using castle windsor with interceptors and asp.net

I'm trying to add logging with aspect orientated programming using castle windsor in plain asp.net, i.e. not MVC
I've added a class that implements the IInterceptor interface and an attribute that inherits from Attribute.
public class LogAttribute : Attribute
{
public Level LogLevel { get; set; }
public LogAttribute(Level level)
{
LogLevel = level;
}
}
public class LoggingInterceptor : IInterceptor
{
public void Intercept(IInvocation invocation)
{
MethodInfo mi = invocation.Method;
LogAttribute[] atts = (LogAttribute[])mi.GetCustomAttributes(typeof(LogAttribute), true);
// if method not marked with InternalUseRestricted attribute, then pass on call
if (atts.Length == 0)
{
invocation.Proceed();
}
else
{
ISeiLogger log = LoggerFactory.GetLogger(mi.DeclaringType.ToString());
//assume only one logging attribute
//log on entry
log.LogEnter(atts[0].LogLevel);
//allow code to continue
invocation.Proceed();
//log on exit
log.LogExit(atts[0].LogLevel);
}
}
}
Now in the global.asax.cs I've added the following:
public partial class Global : System.Web.HttpApplication, IoCProvider
{
private void InitializeIoC()
{
container = new WindsorContainer();
container.Install(new Sei.Aspect.AspectInstaller());
}
public IWindsorContainer Container
{
get { return container; }
}
private static Sei.Logging.ISeiLogger log;
private IWindsorContainer container;
public override void Init()
{
base.Init();
InitializeIoC();
}
and I've created an installer class:
public class AspectInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container, IConfigurationStore store)
{
//container.Register(AllTypes.FromAssembly(Assembly.GetExecutingAssembly()).BasedOn<IInterceptor>().Configure(component => component.LifeStyle.PerWebRequest));
container.Register(Component.For<IInterceptor>().ImplementedBy<LoggingInterceptor>().LifeStyle.PerWebRequest);
container.Register(Component.For<IInterceptor>().ImplementedBy<InternalUseRestrictedInterceptor>().LifeStyle.PerWebRequest);
container.Register(Component.For<IInterceptor>().ImplementedBy<CachingInterceptor>().LifeStyle.PerWebRequest);
}
}
I now want to add the attribute to some arbitary page's code behind class and some arbitary virtual method, as in
[Log(Level.Info)]
protected string Login(string username, string password)
{
DoSomething();
}
This obviously doesn't work. Do I need to change the way I'm instantiating the page (its a page's code-behind class) to use a container? Or is it the way I'm registering the interceptors? I want to be able to use the interceptors on any class going forward and not have to tell the container about each and every class that I have in my application.
Short answer: it's not possible.
Long answer: due to the way ASP.NET Web Forms works, it doesn't let anyone interfere with the page instantiation. Some claim that using a custom PageHandlerFactory lets you do IoC, but this only lets you set properties after the page has been instantiated, which is simply not enough for proxying.
So runtime proxy libraries such as DynamicProxy or LinFu can't do anything about this. But you may be able to use compile-time aspect weavers, such as PostSharp.
Alternatively, make your code-behind as slim as possible, deferring actual logic to Windsor-managed components.

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