I'm trying to pass a URL for a background image to my _Layout.cshtml,
public HomeController()
{
this.ViewData["BackgroundImage"] = "1920w/Stipula_fountain_pen.jpg";
}
and
<body style="background-image: url(#(string.Format("assets/images/{0}", ViewData["BackgroundImage"])))">
...
</body>
but ViewData is always empty inside _Layout.cshtml. Is that working as intended? I'd rather not go down the BaseViewModel/BaseController route as that feels like overkill.
EDIT: It seems as if ViewData set in the constructor isn't actually used, because once an action is executing the collection is empty. If I set ViewData inside the action then that data is passed on to _Layout.cshtml - feels like a bug to me.
You can use an action filter to set ViewData for all controller actions:
public class SetBackgroundUrlAttribute : ActionFilterAttribute
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
base.OnActionExecuted(filterContext);
var result = filterContext.Result as ViewResult;
if (result != null)
{
result.ViewData["BackgroundImage"] = "1920w/Stipula_fountain_pen.jpg";
}
}
}
[SetBackgroundUrl]
public HomeController()
{
}
Or just override OnActionExecuted method of the controller:
public override void OnActionExecuted(ActionExecutedContext context)
{
base.OnActionExecuted(context);
var result = context.Result as ViewResult;
if (result != null)
{
result.ViewData["BackgroundImage"] = "1920w/Stipula_fountain_pen.jpg";
}
}
Expanding on adem caglin's answer I went with this filter attribute, which can take an arbitrary URL:
[AttributeUsage(AttributeTargets.Class|AttributeTargets.Method, AllowMultiple = false)]
public class SetBackgroundUrlAttribute : ActionFilterAttribute
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
base.OnActionExecuted(filterContext);
if (!string.IsNullOrWhiteSpace(this.Url))
{
var result = filterContext.Result as ViewResult;
if (result != null)
result.ViewData["BackgroundImage"] = this.Url;
}
}
public string Url { get; set; }
}
and is used like so:
[SetBackgroundUrl(Url = "1920w/Stipula_fountain_pen.jpg")]
public class HomeController : Controller
{
...
}
Related
Hello I would like to create my custom ActionFilterAttribute for each controller in my application, this attribute should set some ViewBag values. Is ActionFilterAttribute would be fine for it and how to get access to viewbag in ActionFilterAttribute ?
You can do like this
public class SomeMsgAttribute : FilterAttribute, IResultFilter
{
public void OnResultExecuted(ResultExecutedContext filterContext)
{
}
public void OnResultExecuting(ResultExecutingContext filterContext)
{
filterContext.Controller.ViewBag.Msg= "Hello";
}
}
Using:
[SomeMsg]
public ActionResult Index()
{
return View();
}
try this
public class CustomFilterAttribute : ActionFilterAttribute
{
public override void
OnActionExecuting(ActionExecutingContext filterContext)
{
// get the view bag
var viewBag = filterContext.Controller.ViewBag;
// set the viewbag values
viewBag.CustomValue = "CustomValue";
}
}
For ASP.NET Core you can do the following
public class SomeFilterAttribute : IActionFilter
{
public void OnActionExecuting(ActionExecutingContext context)
{
Controller controller = context.Controller as Controller;
controller.ViewBag.CustomValue = customVal;
controller.ViewData["CustomValue "] = customVal;
controller.TempData["CustomValue "] = customVal;
}
}
Then from the controller
[TypeFilter(typeof(ValidateAppFeatureEnabled))]
public IActionResult Index()
{
var foo = ViewBag.CustomValue;
var bar = (type)ViewData["CustomValue"];
var buzz = (type)TempData["CustomValue"];
// Whatever else you need to do
return View();
}
To transfer data from a different controller action
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
EmployeeTrackingSystemAndMISEntities db = new EmployeeTrackingSystemAndMISEntities();
var UserCookie = filterContext.HttpContext.Request.Cookies["UserUniqueID"];
RouteValueDictionary redirectTargetDictionary = new RouteValueDictionary();
redirectTargetDictionary.Add("action", "UserLogIn");
redirectTargetDictionary.Add("controller", "Login");
var TempData = filterContext.Controller.TempData;
TempData["Status"] = "Please log in as Admin";
filterContext.Result = new RedirectToRouteResult(redirectTargetDictionary);
}
i have ActionFilterAttribute like the following
class MyCustomRouteConstraint : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (something == 1) //i know there is no something variable
{
// do something
}
base.OnActionExecuting(filterContext);
}
}
as you can see in my code there is no variable named as something.
but i want to use the variable named as something in my action.
public ActionResult Index()
{
int something = 1;
return View();
}
public ActionResult About()
{
int something = 2;
return View();
}
public ActionResult Contact()
{
int something = 1;
return View();
}
I think what you need is OnActionExecuted. I have not tested.
class MyCustomRouteConstraint : ActionFilterAttribute
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
var something = Convert.ToInt32(filterContext.RouteData.Values["something"]);
if(something == 1)
{
//do something
}
base.OnActionExecuting(filterContext);
}
}
OnActionExecuting is called by the ASP.NET MVC framework BEFORE the action method executes. So it doesn't make sense to initialize your something variable in the action body. But still if you are going to override some method which is called AFTER the action method executes you can probably use ViewBag to init the variable in the controller and then get its value using filterContext.
You use ViewBag for this as well.
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
filterContext.Controller.ViewBag.SommeVariable = "Test";
}
And in your action
public ActionResult Index()
{
var variable = ViewBag.SommeVariable;
return View();
}
I use structuremap dependency injection to do that. See here some snippets:
namespace something.Infrastructure.ActionFilters {
public class PlatformAuthorizeAttribute : AuthorizeAttribute
{
public IRepository<User> UserRepo { get; set; }
public override void OnAuthorization(AuthorizationContext filterContext)
{
base.OnAuthorization(filterContext);
if (WebSecurity.Initialized && filterContext.HttpContext.User.Identity.IsAuthenticated)
{
if (filterContext.HttpContext.User.IsInRole("Banned"))
{
WebSecurity.Logout();
filterContext.Result = new RedirectToRouteResult(
new RouteValueDictionary
{
{"Controller", "Home"},
{"Action", "Banned"},
{"Area", ""}
});
}
UserRepo.Dispose();
UserRepo = null;
}
}
}
}
And then initialize the following mapping in your IoC structuremap class:
public static class IoC
{
public static IContainer Initialize()
{
ObjectFactory.Initialize(x =>
{
x.Scan(scan =>
{
scan.TheCallingAssembly();
scan.WithDefaultConventions();
});
x.SetAllProperties(pset =>
{
pset.WithAnyTypeFromNamespace("something.Infrastructure.ActionFilters");
pset.OfType<IRepository<User>>();
});
});
return ObjectFactory.Container;
}
}
I think this is the cleanest way to provide your action filters with properties. Note that in my example I used a custom AuthorizeAttribute. You will need to change this to ActionFilterAttribute and use the OnActionExecuting method override to access the properties.
Use HttpContext.Items
HttpContext.Items["something"] = 1;
In ActionFilter, you can access it as:
var something = (int)filterContext.HttpContext.Items["something"];
However, your example of action filter is OnActionExecuting; this will execute before any of your Index/About actions executes. So you should initialize 'something' somewhere else as per your needs (for example, inside controller's OnActionExecuting method).
I've got this code.
public ActionResult Index()
{
ReceiptModel model = new ReceiptModel();
try
{
model = new ReceiptModel(context);
}
catch (BussinessException bex)
{
ModelState.AddModelError("Index", bex.MessageToDisplay);
return View("Index");
}
return View(model);
}
BussinesException ir returned from database and then displayed for user. I have to put on every controller method try-catch statement, which is a bit tedious. Is there any easier way how to handle these exceptions?
P.S. All other exceptions are handled with HandleExceptionAttribute
UPDATE:
I used Floradu88 approach. So Now i have something like this.
public sealed class HandleBussinessExceptionAttribute : HandleErrorAttribute, IExceptionFilter
{
public override void OnException(ExceptionContext filterContext)
{
filterContext.Controller.TempData["UnhandledException"] = filterContext.Exception;
filterContext.ExceptionHandled = true;
((Controller)filterContext.Controller).ModelState.AddModelError(
((BussinessException)filterContext.Exception).Code.ToString(),
((BussinessException)filterContext.Exception).MessageToDisplay
);
filterContext.Result = new ViewResult
{
ViewName = this.View,
TempData = filterContext.Controller.TempData,
ViewData = filterContext.Controller.ViewData,
};
}
}
and on Controller action i put
[HandleBussinessExceptionAttribute(Order = 2, ExceptionType = typeof(BussinessException), View = "Login")]
i also tried in exception handler:
filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary(filterContext.RouteData));
and then handle error in action with ModelState.IsValid but values to action comes null. So for now i use first approach. When i have a bit more time i'll try to fix second approach.
Please read the documentation on this part:
http://msdn.microsoft.com/en-us/library/gg416513%28v=vs.98%29.aspx
http://www.asp.net/web-api/overview/web-api-routing-and-actions/exception-handling
http://www.asp.net/mvc/tutorials/older-versions/controllers-and-routing/understanding-action-filters-cs
Too much content to be posted here:
public class NotImplExceptionFilterAttribute : ExceptionFilterAttribute
{
public override void OnException(HttpActionExecutedContext context)
{
if (context.Exception is NotImplementedException)
{
context.Response = new HttpResponseMessage(HttpStatusCode.NotImplemented);
}
}
}
And your controller:
public class ProductsController : ApiController
{
[NotImplExceptionFilter]
public Contact GetContact(int id)
{
throw new NotImplementedException("This method is not implemented");
}
}
According to this post, Create a custom binder and put the model in TempData:
public class AppBinder : DefaultModelBinder
{
protected override void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
base.OnModelUpdated(controllerContext, bindingContext);
controllerContext.Controller.TempData["model"] = bindingContext.Model;
}
}
Register it in global.asax:
ModelBinders.Binders.DefaultBinder = new AppBinder();
Create a BaseController and override the OnException:
protected override void OnException(ExceptionContext filterContext)
{
filterContext.ExceptionHandled = true;
this.ModelState.AddModelError(string.Empty, filterContext.Exception.Message);
filterContext.Result = new ViewResult
{
ViewName = filterContext.RouteData.Values["action"].ToString(),
TempData = filterContext.Controller.TempData,
ViewData = filterContext.Controller.ViewData
};
base.OnException(filterContext);
}
All Actions int The Controllers which inherited from this base controller will show their unhandled exceptions their own view in validation summery (remember to have
#Html.ValidationSummary(true)
in page). it works for me, hope works for you too!
I have set up a global filter for all my controller actions in which I open and close NHibernate sessions. 95% of these action need some database access, but 5% don't. Is there any easy way to disable this global filter for those 5%. I could go the other way round and decorate only the actions that need the database, but that would be far more work.
You could write a marker attribute:
public class SkipMyGlobalActionFilterAttribute : Attribute
{
}
and then in your global action filter test for the presence of this marker on the action:
public class MyGlobalActionFilter : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (filterContext.ActionDescriptor.GetCustomAttributes(typeof(SkipMyGlobalActionFilterAttribute), false).Any())
{
return;
}
// here do whatever you were intending to do
}
}
and then if you want to exclude some action from the global filter simply decorate it with the marker attribute:
[SkipMyGlobalActionFilter]
public ActionResult Index()
{
return View();
}
Though, the accepted answer by Darin Dimitrov is fine and working well but, for me, the simplest and most efficient answer found here.
You just need to add a boolean property to your attribute and check against it, just before your logic begins:
public class DataAccessAttribute: ActionFilterAttribute
{
public bool Disable { get; set; }
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (Disable) return;
// Your original logic for your 95% actions goes here.
}
}
Then at your 5% actions just use it like this:
[DataAccessAttribute(Disable=true)]
public ActionResult Index()
{
return View();
}
In AspNetCore, the accepted answer by #darin-dimitrov can be adapted to work as follows:
First, implement IFilterMetadata on the marker attribute:
public class SkipMyGlobalActionFilterAttribute : Attribute, IFilterMetadata
{
}
Then search the Filters property for this attribute on the ActionExecutingContext:
public class MyGlobalActionFilter : IActionFilter
{
public override void OnActionExecuting(ActionExecutingContext context)
{
if (context.Filters.OfType<SkipMyGlobalActionFilterAttribute>().Any())
{
return;
}
// etc
}
}
At least nowadays, this is quite easy: to exclude all action filters from an action, just add the OverrideActionFiltersAttribute.
There are similar attributes for other filters: OverrideAuthenticationAttribute, OverrideAuthorizationAttribute and OverrideExceptionAttribute.
See also https://www.strathweb.com/2013/06/overriding-filters-in-asp-net-web-api-vnext/
Create a custom Filter Provider. Write a class which will implement IFilterProvider. This IFilterProvider interface has a method GetFilters which returns Filters which needs to be executed.
public class MyFilterProvider : IFilterProvider
{
private readonly List<Func<ControllerContext, object>> filterconditions = new List<Func<ControllerContext, object>>();
public void Add(Func<ControllerContext, object> mycondition)
{
filterconditions.Add(mycondition);
}
public IEnumerable<Filter> GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
{
return from filtercondition in filterconditions
select filtercondition(controllerContext) into ctrlContext
where ctrlContext!= null
select new Filter(ctrlContext, FilterScope.Global);
}
}
=============================================================================
In Global.asax.cs
public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
MyFilterProvider provider = new MyFilterProvider();
provider.Add(d => d.RouteData.Values["action"].ToString() != "SkipFilterAction1 " ? new NHibernateActionFilter() : null);
FilterProviders.Providers.Add(provider);
}
protected void Application_Start()
{
RegisterGlobalFilters(GlobalFilters.Filters);
}
Well, I think I got it working for ASP.NET Core.
Here's the code:
public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
// Prepare the audit
_parameters = context.ActionArguments;
await next();
if (IsExcluded(context))
{
return;
}
var routeData = context.RouteData;
var controllerName = (string)routeData.Values["controller"];
var actionName = (string)routeData.Values["action"];
// Log action data
var auditEntry = new AuditEntry
{
ActionName = actionName,
EntityType = controllerName,
EntityID = GetEntityId(),
PerformedAt = DateTime.Now,
PersonID = context.HttpContext.Session.GetCurrentUser()?.PersonId.ToString()
};
_auditHandler.DbContext.Audits.Add(auditEntry);
await _auditHandler.DbContext.SaveChangesAsync();
}
private bool IsExcluded(ActionContext context)
{
var controllerActionDescriptor = (Microsoft.AspNetCore.Mvc.Controllers.ControllerActionDescriptor)context.ActionDescriptor;
return controllerActionDescriptor.ControllerTypeInfo.IsDefined(typeof(ExcludeFromAuditing), false) ||
controllerActionDescriptor.MethodInfo.IsDefined(typeof(ExcludeFromAuditing), false);
}
The relevant code is in the 'IsExcluded' method.
You can change your filter code like this:
public class NHibernateActionFilter : ActionFilterAttribute
{
public IEnumerable<string> ActionsToSkip { get; set; }
public NHibernateActionFilter(params string[] actionsToSkip)
{
ActionsToSkip = actionsToSkip;
}
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (null != ActionsToSkip && ActionsToSkip.Any(a =>
String.Compare(a, filterContext.ActionDescriptor.ActionName, true) == 0))
{
return;
}
//here you code
}
}
And use it:
[NHibernateActionFilter(new[] { "SkipFilterAction1 ", "Action2"})]
If you have a model-bound parameter in an action method, how can you get to that parameter in an action filter?
[MyActionFilter]
public ActionResult Edit(Car myCar)
{
...
}
public class MyActionFilterAttribute : ActionFilterAttribute
{
public void OnActionExecuted(ActionExecutedContext filterContext)
{
//I want to access myCar here
}
}
Is there anyway to get myCar without going through the Form variables?
Not sure about OnActionExecuted but you can do it in OnActionExecuting:
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
// I want to access myCar here
if(filterContext.ActionParameters.ContainsKey("myCar"))
{
var myCar = filterContext.ActionParameters["myCar"] as Car;
if(myCar != null)
{
// You can access myCar here
}
}
}
}