its said that 1 ViewModel has 1 View. 1 View is for me a UserControl. What if my UserControl has different areas filled with data from different entities, do I have then several Views and need to build several ViewModels? e.g: I display in a UserControl 3 entities: customer(listbox),order(datagrid),product(datagrid). Each of those "data areas" has add+remove buttons and textboxes to enter data.
Actually each of those "data areas" are put in its own GRID having so the posibility to set a individual datacontext.
1.) Should I now create 3 ViewModels CustomerVM,OrderVM and ProductVM?
2.) Are those 3 "data areas" seen as an own sort of separated View, although I have not put them in 3 UserControls.xaml files ???
3.) When this one UserControl is inside a TabControl`s tabpage where do I load the 3 entities related data? Inside the MainViewModel? I want to show/load that data only when the user clicks the tabheader.
But at the same time in this page I need to render some info from another ViewModel. Is it possible to write in action something like return View(Model1, Model2); ?And how could I get access to these ViewModels in this case?
This is probably basic stuff, but I can't find the clear answer anywhere..Lets say I'm doing an MVC (3) application with Entity Framework (EF4), and I have these three classes:
I am trying to pass a view model of mine, which has multiple list in it, to my view. Then in my view i need to edit the different list. Then on my post i need to save the edits. Although, when i pass my viewmodel back to my post, it is empty! Can somebody explain what i am doing wrong? Controller
public class MyViewModel { public MyObject myObject{ get; set; } public List<MyList> myList{ get; set; } }
I have a view with a form strongly typed to MyViewModel This view allows you to enter values for the properties of MyObject, as well as create a list of MyList objects. The List part works fine although I thought that would be the more difficult of the two. Assuming MyObject has a property Description I create a textbox to enter the value as such:
@Html.EditorFor(x => x.myObject.Description); The text box renders with an id of MyObject_Description...The problem is when I post this to my controller action, MyObject does not get bound at all(althought the list items do as they recieve the appropriate IDs of "MyViewModel_MyList[guid].myListValue") What am I doing wrong here?? EDIT: more info The first line of the view is: @model MyApp.ViewModels.MyViewModel And the Action method: [HttpPost] public ActionResult Create(MyViewModel myViewModel) { } I am passing a new MyViewModel into the partial view to begin... public ActionResult Create() { MyViewModel model = new MyViewModel(); return PartialView(model); } EDIT 2 Ok When I render my partial view that contains the forms I call : @{Html.RenderAction("Create", "MyController");} this is called from within a View of type @model IEnumerable<MyApp.Models.MyObject> (this view displays a list of currently existing MyOjects, and at the bottom the partial is rendered to allow the user to add another MyObject to the DB)
I would like to know how i can bind my form values to my strongly typed view from a MultiSelect box. Obviously when the form submits the multi-select box will submit a delittemered string of my values selected...what is the best way to convert this string of values back into a list of objects to attach to my model to be updated?
public class MyViewModel { public List<Genre> GenreList {get; set;} public List<string> Genres { get; set; } }
When updating my model inside the controller i am using UpdateModel like below: Account accountToUpdate = userSession.GetCurrentUser(); UpdateModel(accountToUpdate);
However i need to somehow get the values from the string back into objects. I beleive it may have something to do with model-binders but i can't find any good clear examples of how to do this.
In my application, I need to get data from three tables and display them in 1 view. I have created a .dbml and created a ViewModel in my Models folder to deal with this. Here is my ViewModel:
[Code]....
My web application uses the Default ASP.NET Membership. So User [ u ] is of type aspnet_Users from the default Membership. This ViewModel allows all the CRUD opertation to be carried out. However on the Create and Update operations, I would LOVE some Model Validations, My question is:
1) Would the User [ u ] default validation kick into place in my ViewModel ? Cause I know by default ASP.NET Membership, has Model Validation.
2) For table SUserDetails (which I have created myself, not part of default) how do I add ViewModel validation to it for when someone does an Update or Create?
When I send a strongly typed ViewModel containing other ViewModels nested inside (basically spanning 3 tables into one object) all the data is correctly presented when debugging. However it complains at rendering time with an exception "Compiler Error Message: CS1061: 'object' does not contain a definition for 'Name' and no extension method 'Name' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)"
and the error is thrown from mvc2-rtm-sourcessrcSystemWebMvcMvcViewPageControlBuilder.cs method: ProcessGeneratedCode line 19
When I first heard about ASP.NET MVC, I was thinking that would mean applications with three parts: model, view, and controller.
Then I read NerdDinner and learned the ways of repositories and view-models. Next, I read this tutorial and soon became sold on the virtues of a service layer. Finally, I read the Fluent Validation documentation, and I'll be darned if I didn't end up writing a bunch of validators.
Tonight, I took a step back and thought about what had become of my project. It seems to have become the victim of the design pattern equivalent of "feature creep". Somehow I'd gone from Model-View-Controller to Model-Repository-Service-Validator-View-ViewModel-Controller. You want loosely coupled and DRY? We got your loosely coupled and DRY right here! But I'm wondering if this could be a case of too much of a good thing.
Am I right to be concerned? Or is this actually not as crazy as it sounds? On one hand, it seems crazy to have so many layers. On the other hand, every layer has a clearly defined purpose that makes sense to me. Have your MVC applications turned into MRSVVVMC apps too? If not, what do they look like? Where's that right balance?
I'm new to .Net development, and now are following NerdDinner tutorial. Just wondering if any of you would be able to tell me What is the differences between ViewData and ViewModel(all I know is they are used to pass some form of data from controller to view) and perhaps tell me on what situation should I use ViewData instead of ViewModel and vice versa
[HttpPost] public ActionResult Edit(int id, FormCollection fc) { Movie movie = ( from m in _ctx.Movie.Include("MovieActors") where m.MovieID == id select m ).First(); MovieActorViewModel movieActor = new MovieActorViewModel(movie); if (TryUpdateModel(movieActor)) { _ctx.ApplyPropertyChanges(movieActor.Movie.EntityKey.EntitySetName, movieActor.Movie); _ctx.SaveChanges(); } return View(movieActor); }
However, I am not sure how to test this, and in general would much rather have the method take a typed model like:[HttpPost] public ActionResult Edit(MovieActorViewModel movieActor) Is this possible? What changes to my MovieActorViewModel class do I need to make in order to enable this? That class looks like this:
public class MovieActorViewModel { public Movie Movie { get; set; } public Actor Actor { get; set; } public PublisherDealViewModel(Movie movie) { this.Movie = movie; this.Actor = ( from a in this.Movie.Actors where a.ActorID == 1 select a ).First(); } }
The view is typed (inherits ViewPage) simple:
<% using (Html.BeginForm()) {%> Movie Title: <%= Html.TextBoxFor(model=>model.Movie.Title) %><br/> Actor Name: <%= Html.TextBoxFor(model=>model.Actor.Name) %> <% } %>
I have used IDataErrorInfo Validation for my Model.
But when I use these model classes inside a view model, the validation does not happen.
sample viewmodel below
[code]....
Now, if Category or Subcategory classes are directly used as models for view, the validation works fine. But, if CategoryViewModel is used, no validation occurs.
A table can be used to automatically sense Model. But when I get more than one table after the SQL query is a DataTable. When this DataTable to return View (DataTable) later. In the aspx file, can automatically perceive it as the Model, as the self-paragraphs?
I have a table called "question" which consists of various columns, including 3 columns of type: bit.
these columns are: yes, no, maybe.
The corresponding viewmodel has 3 properties of type boolean. The controller returns the views, which are based on the viewmodels.
By default MVC create checkboxes for boolean types, the thing is that the properties have to be related, only 1 should be checked at a time. That is why I want to change the checkboxes to radiobuttons.
After some search on the web I tried various things, in the end I got the create working by putting three radiobuttons, tied to the same boolean field, adjusing the values.
But how to edit a question? The view is filled with data from the database, putting 1 of the 3 booleans to true.
What should my view be like, to display 3 radiobuttons, mapped to the 3 boolean types?
public class AccessRequestViewModel { public Request Request { get; private set; } public SelectList Buildings { get; private set; } public List<Person> Persons { get; private set; } }
So in my application there must be at least 1 person for an access request. What approach might you use to validate? I don't want this validation to happen in my controller which would be simple to do. Is the only choice a custom validation attribute?
Edit: Currently performing this validation with FluentValidation (nice library!)
RuleFor(vm => vm.Persons) .Must((vm, person) => person.Count > 0) .WithMessage("At least one person is required");
http://weblogs.asp.net/shijuvarghese/archive/2010/02/01/view-model-pattern-and-automapper-in-asp-net-mvc-applications.aspxThat's Great, but it is in #C like every other tutorial I find. Note his ContactViewModelWell here is mine:
[Code]....
How do I add validation in the same fashion as he did in his blog in VB?
I'm curious as to what people consider better practice, between duplicating model structure in the view model and using a mapping tool to move data between the two, or aggregate the model inside the view model, i.e. have a property on the view model class that is a reference to the actual model. Which is considered a better approach in general?
I'm making an MVC2 app to manage billing schemes. These billing schemes can be of various types, e.g. daily, weekly, monthly, etc. and all types have their specific properties. My class structure looks like this:
public abstract class BillingScheme { /* basic billing scheme properties */ } public class BillingSchemeMonthly : BillingScheme { public string SpecificMonths; } //etc. for other scheme types
I retrieve a billing scheme through the base class using the billing scheme ID, and it gives me an object of the correct type. The property SpecificMonths maps to a database varchar field that contains a ;-separated string of month numbers. I want to split this to an array so I can create a list of checkboxes and I'd preferably do this with a facade property in a viewmodel. I could do it right inside the view but that seems to go against the MVC pattern.
The problem is I can only create this viewmodel specifically for a BillingSchemeMonthly, and I can't cast a BillingSchemeMonthly to a BillingSchemeMonthlyViewModel. I'd rather not implement a clone method in the viewmodel since the entire billing scheme is quite large and the number of properties may grow.
I am just getting started with MVC after many years of WebForms development.
I have a very simple page with two textbox fields, one called Input where a user will enter something, and one called Output where I want to return some string after they post the form, much like a postback scenario in WebForms. I have the View connected to a ViewModel for strong typing.
The ViewModel:
[Code]....
The View:
[Code]....
The Controller:
[Code]....
The problem I have is that the output text "Here is some response" never gets displayed, even though I modify the value in the HttpPost method and return the viewmodel to the view. Unless (just tried it) I set the textarea to disabled with:
[Code]....
Can someone explain this behavior? It seems as some "magic" assumes that whatever was in the input fields before the HttpPost should also be there after the post, similar to what ViewState does in WebForms.
but what if I wanted to bind to collection items within the ViewModel. I'm not sure if it's possible. Here's what I have:
My ViewModel:
[code]....
I'm getting the following error: Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions.
Is there a way to stuff my ViewModel into an Ajax.ActionLink? edit I'd like to take my 5 search fields on my page which are bind to a view model and send it along my .ActionLink as my object value parameter.
I have a viewmodel with a property of a model class type. I set some properties in the model class to be able to show it to the user but then when I make a post, the model gets validated. How to overcome this? I don't want to enforce the DataAnnotations contraint in this case....
public class TheViewModel { TheModel TheModel { get; set;} } [code]...
