I'm trying to pass ViewData to my asp.net mvc masterpage for an mvc usercontrol that I keep on a masterpage. For example, I created a dropdownlist of names as an mvc usercontrol and I put that in my masterpage.
The problem I am running into is passing the ViewData to the masterpage. I found this article from Microsoft which has a decent solution but I was wondering if there are other "better" solutions out there. The thing I don't like about the solution in the link is that I have to change every controller to inherit from a new controller class.
http://www.asp.net/learn/MVC/tutorial-13-cs.aspx
Edit: The problem I am looking at is the fact that if I place a user control in my masterpage that relies on ViewData, I have to REPEATEDLY include that ViewData for every single page that uses said masterpage. It's possible the solution in the link above is the best solution but I was hoping there were other alternatives.
The master page already has access to the ViewData. If you want strongly typed access to it, you need to do two things:
Put the master page stuff in a base class (e.g. CommonViewData)
Have you master page inherit from the generic ViewMasterPage<> class:
" %>
Could you possibly use the OnActionExecuting method on a base controller class and populate the view data there?
Something like:
protected override void OnActionExecuting(ActionExecutingContext context)
{
context.Controller.ViewData.Model = GetDataForControl();
}
I haven't tried it so it's just a thought...
For what it's worth, I am using the method from that tutorial in a current project and it works very well.
What you can also do, if it is data that is somewhat static (like a menu that doesn't change much), is to put the object on the cache so your database isn't called for every controller initialisation.
I usually use an abstract controller class for my MasterPage, it is the best solution, because the MasterPage is like an "abstract view". But I override the MasgerPageController View() method to include the viewdata.
protected override ViewResult View(string viewName, string masterName, object model)
{
this.ViewData["menu"] = this.PagesRepository.GetPublishPages();
return base.View(viewName, masterName, model);
}
I don't quite get your problem...
The problem I am looking at is the fact that if I place a user control in my masterpage that relies on ViewData, I have to REPEATEDLY include that ViewData for every single page that uses said masterpage.
Well yeah... of course you do. If you have a usercontrol in your master page then of course you're going to have to pass the required data for that usercontrol for every action & view that uses that masterpage.
It's not like you have to repeat yourself if you are just inheriting from a base controller.
Is your issue the fact that some controllers have actions that both do and don't call views that derive from that particular masterpage? So therefore if you are implementing a base controller, the actions that don't use that particular masterpage will still have the viewdata for it...? (If all that makes sense ;-)
I think the solution suggested does work but not the ideal solution. If we put the code in the BaseController constructor it is going to be called even for Action methods which does not have a MasterPages (e.g Post methods and Ajax methods).
I think a better solution(not ideal) is to call Html.Action method in the Master page.
Related
I have a user control which shows list of latest announcements. This user control would be used in almost 90% of my pages. Now my concern is how to pass data to this user control for latest announcements.
My first approach is to make a base controller and in Initialise method I pass data to user control via ViewBag/ViewData. All my other controllers derive from this base controller. This looks nice but my concern is that it may become an overkill for some simple solution existing already out there. Also I would need to make sure that no controller ever fiddles with my Viewdata/Viewbag data meant for my usercontrol.
Please let me know if this is correct way of proceeding ahead or there exists some better solution.
Thanks
Assuming you have a "user control" (you should try to refer to them as partial view's in MVC) that looks like this:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Announcement>>" %>
This means your partial view expects a list of Announcement objects.
Now, the question is - where are you rendering this partial view?
You could be doing it from a master page, you could be doing it from a view, or you could be doing it from another partial view.
Either way, the code to render the partial needs to look like this:
<% Html.RenderPartial("LatestAnnouncements", announcements) %>
But - where do you get the announcements from.
Assuming you have a Repository/DAL/helper method to get the latest announcements - i think you should have the ViewModel's you require inheriting from a base ViewModel:
public class AnnouncementViewModelBase
{
protected IEnumerable<Announcement> GetAnnouncements()
{
// call DAL
}
}
Then any master/view/partial that needs to render the latest announcements partial should be bound to a ViewModel which inherits from that base view model.
In the cases where the master/view/partial is not strongly-typed (e.g dynamic view), you can stick it in the ViewData. But if you have organized your view's correctly this shouldn't be required.
Is this the kind of thing you're after? How to pass data from view to UserControl in ASP.NET MVC?
You should use RenderAction in this kind of scenario, so that you do not have bother to pass the required data in each action method of your controllers.
I think the best way would be to use #Html.Action. This would allow me to call my actions dedicated to my usercontrols data and I can call it from anywhere.
So if there is some global state that every view of an MVC app will need to render ... for example: IsUserLoggedOn and UserName ... whats the appropriate way of getting that information to every view?
I understand that that part of the view should be in the master page or in a partial view thats added to the other views. But whats a good way to make sure the 'global' model data is passed to the view every time from all the relevant controllers and actions?
After asking this, I found this good blog post by Steve Sanderson:
http://blog.stevensanderson.com/2008/10/14/partial-requests-in-aspnet-mvc/
He suggests three different approaches:
Use a base controller class or ActionFilter to add the relevant model to the ViewData[] collection every time. I think a few people have suggested that sort of thing already.
Use Html.RenderAction() in the view ... and as he says:
If someone tells you that internal
subrequests are bad because
it “isn’t MVC”, then just bite them on
the face immediately. Also ask them
why they’re still willing to use Ajax,
and even <IMG> tags for that matter,
given that both are a form of
subrequest.
Use 'Partial Requests' (he provides the code for this on his blog) which allow one controller to nest calls to other controllers into a sortof nested ViewData structure.
codeulike - see the answer to a similar question asked at exactly the same time as this:
ASP.NET MVC displaying user name from a Profile
in a nutshell, basically create a base controller that's inherited by all your other controllers. the base controller then has an override function that carries thro' to all 'child' controllers. rather than duplicate the code, take a look at my answer above and give it a try..
cheers...
You could create base class for viewmodel which contains shared information and inherit that for each viewmodel.
public class ViewModelBase
{
// shared data
}
public class Page1ViewModel : ViewModelBase
{
// page 1 data
}
In masterpage you could use that base class
Inherits="System.Web.Mvc.ViewMasterPage<ViewModelBase>"
and in each view use those derived classes
Inherits="System.Web.Mvc.ViewPage<Page1ViewModel>"
I make heavy use of View Components in some of the larger applications I've built in Monorail - What is the equivalent approach in ASP.Net MVC for a view component, that can support sections etc.?
Actually you have several options to create the equivalent of a ViewComponent in ASP.NET MVC, depending in the complexity of your component. I use these two approaches which are the more mvc-ish of the options I am aware of.
1:
The simplest thing is to create a ViewUserControl and display it using Html.RenderPartial with the helper. The ViewUserControl is a simple piece of markup with no backing controller (I think you can put a codebehind file if you want).
Optionally, you can pass a model object or the entire ViewData dictionary to the view when calling RenderPartial, like this:
<% Html.RenderPartial("TopBar", model); %>
"TopBar" is an ascx page. This works anywhere, in master pages and in normal views.
2:
If you want your component to have more complicated logic or to access datasources, IoC, etc, then you can use Html.RenderAction which is an extension method found in the Microsoft.Web.Mvc assembly. I am using this out of the mvccontrib distribution. It works like this, you need to create a normal controller with all the logic you need, then create some views and all of these things become your component, for example:
public class AboutComponentController : Controller {
public IRepository Repository{ get; set; }
public ActionResult Detail() {
var lastEvent = Repository.FindAll<Auditoria>().FirstOrDefault();
return View(lastEvent);
}
}
Notice how I have a reference to an IRepository which is going to be injected with IoC (Windsor in my case) and I can do anything a normal controller would do.
Now, in any page (master or normal) where you want to use your component, import Microsoft.Web.Mvc and call Html.RenderAction with the appropriate parameters. This will create a mini mvc pipeline that creates the controller, resolves the view, etc., just like a Monorail ViewComponent. I prefer to use the lambda based variation of the method, like this:
<% Html.RenderAction<AboutComponentController>(x => x.Detail("a message"));%>
Unfortunately, the only way to pass parameters is to use the method call itself, which in turn must be unique in the controller. Still needs some work to resemble a ViewComponent.
I don't use masterpages or layouts in the views of my components since they are composition elements themselves.
Remember that when using the Webforms view engine, you can have strongly typed views if you like to have intellisense when using the Model variable in code blocks.
The beauty of this is that you can mix view engines with these approaches, I usually create the components in nvelocity and display them in aspx pages, etc.
I now there can be issues with caching of the partial views but I haven't run into any so far. I am sure there are other options (like subcontrollers in mvccontrib) but this is usually enough for simple cases. Of course you can use normal ASP.net components in your aspx view pages but that would be cheating right? hehe. I hope it helps.
Phil Haack blogged about creating areas to group controllers into sub-folders/sections similar to MonoRails.
The 'RenderPartial()' method in ASP.NET MVC offeres a very low level of functionality. It does not provide, nor attempt to provide a true 'sub-controller' model *.
I have an increasing number of controls being rendered via 'RenderPartial()'. They fall into 3 main categories :
1) Controls that are direct
descendants of a specific page that
use that page's model
2) Controls that are direct
descendants of a specific page that
use that page's model with an
additional key of some type.
Think implementation of
'DataRepeater'.
3) Controls that represent unrelated
functionality to the page they appear
on. This could be anything from a
banner rotator, to a feedback form,
store locator, mailing list signup.
The key point being it doesn't care
what page it is put on.
Because of the way the ViewData model works there only exists one model object per request - thats to say anything the subcontrols need must be present in the page model.
Ultimately the MVC team will hopefully come out with a true 'subcontroller' model, but until then I'm just adding anything to the main page model that the child controls also need.
In the case of (3) above this means my model for 'ProductModel' may have to contain a field for 'MailingListSignup' model. Obviously that is not ideal, but i've accepted this at the best compromise with the current framework - and least likely to 'close any doors' to a future subcontroller model.
The controller should be responsible for getting the data for a model because the model should really just be a dumb data structure that doesn't know where it gets its data from. But I don't want the controller to have to create the model in several different places.
What I have begun doing is creating a factory to create me the model. This factory is called by the controller (the model doesn't know about the factory).
public static class JoinMailingListModelFactory {
public static JoinMailingListModel CreateJoinMailingListModel() {
return new JoinMailingListModel()
{
MailingLists = MailingListCache.GetPartnerMailingLists();
};
}
}
So my actual question is how are other people with this same issue actually creating the models. What is going to be the best approach for future compatibility with new MVC features?
NB: There are issues with RenderAction() that I won't go into here - not least that its only in MVCContrib and not going to be in the RTM version of ASP.NET-MVC. Other issues caused sufficent problems that I elected not to use it. So lets pretend for now that only RenderPartial() exists - or at least that thats what I've decided to use.
Instead of adding things like MailingListSignup as a property of your ProductModel, encapsulate both at the same level in a class like ProductViewModel that looks like:
public class ProductViewModel() {
public ProductModel productModel;
public MailingListSignup signup;
}
Then get your View to be strongly-typed to the ProductViewModel class. You can access the ProductModel by calling Model.productModel, and you can access the signup class using Model.signup.
This is a loose interpretation of Fowler's 'Presentation Model' (http://martinfowler.com/eaaDev/PresentationModel.html), but I've seen it used by some Microsoft devs, such as Rob Conery and Stephen Walther.
One approach I've seen for this scenario is to use an action-filter to populate the data for the partial view - i.e. subclass ActionFilterAttribute. In the OnActionExecuting, add the data into the ViewData. Then you just have to decorate the different actions that use that partial view with the filter.
There's a RenderPartial overload I use that let's you specify a new ViewData and Model:
RenderPartial code
If you look at the previous link of the MVC source code, as well as the following (look for RenderPartialInternal method):
RenderPartialInternal code
you can see that if basically copies the viewdata you pass creating a new Dictionary and sets the Model to be used in the control. So the page can have a Model, but then pass a different Model to the sub-control.
If the sub-controls aren't referred directly from the main View Model, you could do the trick Marc Gravell mentions to add your custom logic.
One method I tried was to use a strongly typed partial view with an interface. In most situations an agregated ViewModel is the better way, but I still want to share this.
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IMailingListSignup>" %>
The Viewmodel implements the interface
public class ProductViewModel:IMailingListSignup
Thats not perfect at all but solves some issues: You can still easily map properties from your route to the model. I am not shure if you can have a route parameter map to the properties of MailingListSignup otherwise.
You still have the problem of filling the Model. If its not to late I prefer to do it in OnActionExecuted. I dont see how you can fill a Model in OnActionExecuting.
I'm using a few (2 or 3) master pages in my ASP.NET MVC application and they must each display bits of information from the database. Such as a list of sponsors, current fundings status etc.
So my question was, where should I put these master-page database calling code?
Normally, these should goes into its own controller class right? But then that'd mean I'd have to wire them up manually (e.g. passing ViewDatas) since it is out of the normal routing framework provided by the MVC framework.
Is there a way to this cleanly without wiring ViewData passing/Action calls to master pages manually or subclassing the frameworks'?
The amount of documentation is very low... and I'm very new to all this including the concepts of MVC itself so please share your tips/techniques on this.
One way to do this is to put in the masterpage view the hook for the ViewData and then you define a BaseController : Controller (or multiple base classes) where you do all the db calls you need.
What you wanna do is quite the same thing described in this articles.
I hope this helps!
Regards
Great question. You have several options available to you.
Have a jQuery call on your masterpage that grabs the data you need from a controller and then populate your fields using jQuery again.
Your second option is to create user controls that make their own calls to the controller to populate their information.
I think the best choice is creating controls for the region of your masterpage that has data that needs to be populated. Thus leaving your masterpage to strictly contain design elements. Good luck.
If you don't mind strongly typed view data, you can put all the master page data in a common base class for viewData. You can set this data in the base class's constructor. All your views requiring additional data will then need strongly typed viewdata that inherits from this base class.
To allow a call to View() in your controllers without any explicit viewdata you can override View in your ControllerBase:
protected override ViewResult View(string viewName, string masterName, object model)
{
if (model == null)
{
model = new ViewDataBase();
}
return base.View(viewName, masterName, model);
}