I want to use a view with model as IEnumerable type some thing like this
#model IEnumerable<WCG.Data.EntityObjects.FaxHistory>
Note:-I have classes as FaxHistory.cs(Main class where variables are declared)
FaxHistoryBo.cs
FaxHistoryDao.cs
IfaxHIstoryDao.cs
FaxHistoryController.cs
FaxHistorymodel.cs
Related
Very simple question: in a strict MVC design pattern we want to keep Model, View and Controller can the View layer know which custom data classes are defined in the model?
As example:
I got a CarViewController in the view layer and a Car object in the model layer. Whenever the model layer changes the controller object that "sits" between the model and the view notifies the CarViewController and in my current implementation passes a copy of the updated car data as an instance of the Car class. Is this correct?
My gut instinct would have said no because I would not want the view layer to know the details of the model objects. It is not strict decoupling. However if I pass specific values instead of passing the custom data model I would need to stick to standard/primitive values (E.g. int as number of wheels) and it may require more coding.
Have I understood MVC correctly? Is there any reason why the view should not know the custom classes of the model layer?
If I am understanding your question correctly, I would say that your view needs to know the details of your Car object in most of the cases. You can utilize metadata in this way like this:
Model:
public class Car
{
[Display(Name = "Number of wheels")]
public int Wheels { get; set; }
}
View:
#model Namespace.Models.Car
#* This will display whatever your [Display(Name="Value")] decorator defines
as a display name, also the editor will respect the data type decorator. *#
#Html.LabelFor(m => m.Wheels)
#Html.EditorFor(m => m.Wheels)
In this case if you basically pass down a primitive then all metadata for your model is lost.
Hello everyone I have checked my controller and view it seems there is no problem but I get System Colletion error.
Here is my controller
public ViewResult Index()
{
return View(db.banner.ToList());
}
Here is My View
{
#model IEnumerable<icerik.Models.banner>
}
And I get this error
The model item passed into the dictionary is of type 'System.Collections.Generic.List`1[icerik.Models.banner]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[icerik.Models.contents]'.
Maybe you have a partial in your main view:
#Html.Partial("SomePartial")
and this partial is strongly typed to IEnumerable<contents>:
#model IEnumerable<icerik.Models.contents>
So make sure that you are passing the correct model to this partial. If you do not specify anything to the Partial helper (as in my example) the main model will be passed to this partial.
So always specify the correct model:
#Html.Partial("SomePartial", SomeModelInstance)
This question is an extension of this Related question.
Taking Derick's advice, I now have my data in the correct shape. i.e. I have a collection of Department objects, each of which have a collection of Users.
Again following Derick's advice I'm trying to render a CollectionView of CompositeView's
My collection view looks like this
class UserListView extends Backbone.Marionette.CollectionView
itemView: UserCompositeView
id: "user-list"
appendHtml: (collectionView, itemView, index) =>
itemModel = #collection.at(index)
itemView = new UserCompositeView
model: itemModel
collection: itemModel.get("users")
collectionView.$el.append itemView.el
and my Composite View looks like this:
class UserCompositeView extends Backbone.Marionette.CompositeView
itemView: UserItemView
itemViewContainer: '#users'
If I don't override the appendHtml method then the view renders but it only renders the properties of the Department model. It doesn't render the users collection.
When I override the appendHtml method in the CollectionView so I can pass a model (a Department object) and a collection of users but one or both of them seem to be the wrong type of objects because the Marionette bindTo function is complaining that the object has no 'on' method.
What am I doing wrong?
What does itemModel.get("users") return?
If this is returning a JavaScript array or object literal, that would be the problem. You have to pass a valid Backbone.Collection as the collection parameter, not just an array of objects.
collection: new Backbone.Collection(itemModel.get("users"))
You can also look into using backbone-relational which will let you define models that have submodels or subcollections.
I lack understanding of some basic MVC concepts, despite all my searching.
I created an MVC project in Visual Studio, which contains the partial view _LogOnPartial.shtml. I just want to access information within the view pertaining to the user, to put in a user dropdown menu. When I try to put this at the top of the partial view cshtml page I get the above error:
#model MyProject_MVC.Models.UserRepository
When I try this I also get an error:
#Html.Partial("_LogOnPartial", MyProject_MVC.Models.UserRepository)
'MyProject_MVC.Models.UserRepository' is a 'type', which is not valid in the given context
You have to provide an instance of MyProject_MVC.Models.UserRepository to the partial view. _LogOnPartial is strongly-typed to that type. It lets you access its public members at compile time and decide how you can display it in your view.
If you want to use your own type in that view, first you have to change the type that is strongly-typed to it.
#model MyProject_MVC.Models.UserRepository
Then you have to create an instance of that type in your action method and pass it to the view as the model or a property of the model.
public ActionResult LogOn()
{
return View(new UserRepository());
}
Now you can access this instance as Model object in your view.
#Html.Partial("_LogOnPartial", Model);
#model _LogOnPartial.Models.UserRepository should probably be: #model MyProject_MVC.Models.UserRepository
and for the last part, you have to provide and instance of the type UserRepository as the second parameter, not the type itself.
I hope I'm not missing something incredibly obvious here but is there any reason why model binder is always having trouble binding a view model that inherits from a collection?
Lets say I want to show a paged list and display a combo box and add button above it (dealing with simple lists). Involved classes would look like:
public class PagedList<T> : List<T>
{
public int TotalCount { get; set; }
}
And then a view model that looks like:
public class MyViewModel : PagedList<ConcreteModel>
{
public IEnumerable<ChildModel> List { get; set; }
public int? SelectedChildModelId { get; set; }
}
So in the view (Razor):
#model MyViewModel
#using (Html.BeginForm())
{
#Html.DropDownListFor(model => model.SelectedChildModelId, new SelectList(Model.List, "ChildModelId", "DisplayName"))
}
And the controller HttpPost action:
public ActionResult(MyViewModel viewModel)
{
...
}
The above will cause viewModel in ActionResult to be null. Is there a logical explanation for it? From what I can tell it's specific only to view models that inherit from collections.
I know I can get around it with custom binder but the properties involved are primitive types and there isn't even any generics or inheritance.
I've reworked the view models to have the collection inherited type as properties and that fixes the issue. However I'm still scratching my head over why the binder breaks down on it. Any constructive thoughts appreciated.
To answer my own question: All my models that have anything to do with collections no longer inherit from generic list or similar but instead have a property of the required collection type. This works much better because when rendering you can use
#Html.EditorFor(m => m.CollectionProperty)
And create a custom editor under Views/Shared/EditorTemplates for contained type. It also works beautifully with model binder since all individual items from collection get a index and the binder is able to auto bind it when submitted.
Lesson learned: if you plan to use models in views, don't inherit from collection types.
Sometimes model binding to a collection works better if the data in the form post is formatted differently.
I use a plugin called postify.
http://www.nickriggs.com/posts/post-complex-javascript-objects-to-asp-net-mvc-controllers/