How can i send two Model from controller to view using same action
Let's assume your two models are instances of MyModel and MyOtherModel.
I can think of two options:
Pass MyModel as the Model and put MyOtherModel in the ViewBag.
Create class MyBigModel with a property containing MyModel and another property containing MyOtherModel and pass MyBigModel as the Model.
Option 1 is really not your ideal solution. Since your model should relate to your view (that's why I prefer the name ViewModel), I'd really go for option 2.
Option 2 would look like this:
public class MyBigModel
{
public MyModel { get; set; }
public MyOtherModel { get; set; }
}
Use ViewModel - create one more model that would contain both of the models, and send that to view
public class MyCustomViewModel
{
public MyFirstModel First { get; set; }
public MySecondModel Second { get; set; }
}
And in controller
public ActionResult Action()
{
MyFirstModel first = new MyFirstModel();
MySecondModel second = new MySecondModel();
MyCustomViewModel model = new MyCustomViewModel();
model.First = first;
model.Second = second;
return View(model);
}
Generally, as the name suggests, you should be using custom ViewModel for every view in your application, and then use tools like AutoMapper to map those view models back and forth to domain models. View models give you great flexibility in composing your view, as you can give any shape and form to them without changing domain.
Related
I have a constants values such as "Required","Optional", and "Hidden". I want this to bind in the dropdownlist. So far on what I've done is the below code, this is coded in the view. What is the best way to bind the constant values to the dropdownlist? I want to implement this in the controller and call it in the view.
#{
var dropdownList = new List<KeyValuePair<int, string>> { new KeyValuePair<int, string>(0, "Required"), new KeyValuePair<int, string>(1, "Optional"), new KeyValuePair<int, string>(2, "Hidden") };
var selectList = new SelectList(dropdownList, "key", "value", 0);
}
Bind the selectList in the Dropdownlist
#Html.DropDownListFor(model => model.EM_ReqTitle, selectList)
Judging by the property EM_RegTitle I'm guessing that the model you're using is auto-generated from a database in some way. Maybe Entity Framework? If this is the case, then you should be able to create a partial class in the same namespace as your ORM/Entity Framework entities and add extra properties. Something like:
public partial class MyModel
{
public SelectList MyConstantValues { get; set; }
}
You can then pass your SelectList with the rest of the model.
There are usually hangups from using ORM/EF entities through every layer in your MVC app and although it looks easy in code examples online, I would recommend creating your own View Model classes and using something like AutoMapper to fill these views. This way you're only passing the data that the views need and you avoid passing the DB row, which could contain other sensitive information that you do not want the user to view or change.
You can also move the logic to generate your static value Select Lists into your domain model, or into a service class to help keep reduce the amount of code and clutter in the controllers.
Hope this helps you in some way!
Example...
Your View Model (put this in your "Model" dir):
public class MyViewModel
{
public SelectList RegTitleSelectList { get; set; }
public int RegTitle { get; set; }
}
Your Controller (goes in the "Controllers" dir):
public class SimpleController : Controller
{
MyViewModel model = new MyViewModel();
model.RegTitle = myEfModelLoadedFromTheDb.EM_RegTitle;
model.RegTitleSelectList = // Code goes here to populate the select list.
return View(model);
}
Now right click the SimpleController class name in your editor and select "Add View...".
Create a new view, tick strongly typed and select your MyViewModel class as the model class.
Now edit the view and do something similar to what you were doing earlier in your code. You'll notice there should now be a #model line at the top of your view. This indicates that your view is a strongly typed view and uses the MyViewModel model.
If you get stuck, there are plenty of examples online to getting to basics with MVC and Strongly Typed Views.
You would prefer view model and populate it with data in controller.
class MyViewModel
{
public string ReqTitle { get; set; }
public SelectList SelectListItems { get; set; }
}
Then you can use:
#Html.DropDownListFor(model => model.EM_ReqTitle, model.SelectListItems)
I have an action that creates a List and returns it to my view..
public ActionResult GetCustomers()
{
return PartialView("~/Views/Shared/DisplayTemplates/Customers.cshtml", UserQueries.GetCustomers(SiteInfo.Current.Id));
}
And in the "~/Views/Shared/DisplayTemplates/Customers.cshtml" view I have the following:
#model IEnumerable<FishEye.Models.CustomerModel>
#Html.DisplayForModel("Customer")
Then I have in the "~/Views/Shared/DisplayTemplates/Customer.cshtml" view:
#model FishEye.Models.CustomerModel
#Model.Profile.FirstName
I am getting the error:
The model item passed into the dictionary is of type System.Collections.Generic.List`1[Models.CustomerModel]', but this dictionary requires a model item of type 'Models.CustomerModel'.
Shouldn't it display the Customer.cshtml for every item in the collection in the Customers.cshtml?
Help!
I am not sure why you are calling a partial view like this. If it is a Customer Specific view, why not put it under Views/Customer folder ? Remember ASP.NET MVC is more of Conventions. so i would always stick with the conventions (unless abosultely necessary to configure myself) to keep it simple.
To handle this situation, i would do it in this way,
a Customer and CustomerList model/Videmodel
public class CustomerList
{
public List<Customer> Customers { get; set; }
//Other Properties as you wish also
}
public class Customer
{
public string Name { get; set; }
}
And in the action method, i would return an object of CustomerList class
CustomerList customerList = new CustomerList();
customerList.Customers = new List<Customer>();
customerList.Customers.Add(new Customer { Name = "Malibu" });
// you may replace the above manual adding with a db call.
return View("CustomerList", customerList);
Now there should be a view called CustomerList.cshtml under Views/YourControllerName/ folder. That view should look like this
#model CustomerList
<p>List of Customers</p>
#Html.DisplayFor(x=>x.Customers)
Have a view called Customer.cshtml under Views/Shared/DisplayTemplates with this content
#model Customer
<h2>#Model.Name</h2>
This will give you the desired output.
Your view is expecting a single model:
#model FishEye.Models.CustomerModel // <--- Just one of me
You're passing it an anonymous List:
... , UserQueries.GetCustomers(SiteInfo.Current.Id) // <--- Many of me
You should change your view to accept the List or determine which item in the list is supposed to be used before passing it into the View. Keep in mind, a list with 1 item is still a list and the View is not allowed to guess.
Earlier today, a helpful person (here on Stack Overflow) pointed me towards AutoMapper, I checked it out, and I liked it a lot! Now however I am a little stuck.
In my Code First MVC3 Application, on my [Home/Index] I need to display the following information from my Entities:
List of Posts [ int Id, string Body, int Likes, string p.User.FirstName, string p.User.LastName ]
List of Tags [int Id, string Name]
List of All Authors that exist on my Database [ string UrlFriendlyName ]
So far I have managed only point 1 in the list by doing the following for my Index ViewModel:
public class IndexVM
{
public int Id { get; set; }
public string Body { get; set; }
public int Likes { get; set; }
public string UserFirstName { get; set; }
public string UserLastName { get; set; }
}
And on the Home Controller, Index ActionMethod I have:
public ActionResult Index()
{
var Posts = postsRepository.Posts.ToList();
Mapper.CreateMap<Post, IndexVM>();
var IndexModel = Mapper.Map<List<Post>, List<IndexVM>>(Posts);
return View(IndexModel);
}
Finally on my View I have it strongly typed to:
#model IEnumerable<BlogWeb.ViewModels.IndexVM>
And I am passing each Item in the IndexVM IEnumberable to a Partial View via:
#foreach (var item in Model)
{
#Html.Partial("_PostDetails", item)
}
My question is, how can I also achieve point 2 and 3, whilst not breaking what I've achieved in point 1.
I tried putting the stuff I currently have for IndexVM into a SubClass, and having a List Property on the Parent class, but it didn't work.
From the ASP.NET MVC2 In Action Book:
Some screens are more complex than a single table. They may feature
multiple tables and additional fields of other data: images, headings,
subtotals, graphs, charts, and a million other things that complicate
a view. The presentation model solution scales to handle them all.
Developers can confidently maintain even the gnarliest screens as long
as the presentation model is designed well. If a screen does contain
multiple complex elements, a presentation model can be a wrapper,
composing them all and relieving the markup file of much complexity. A
good presentation model doesn’t hide this complexity—it represents it
accurately and as simply as possible, and it separates the data on a
screen from the display.
Make a ViewModel that represents your screen. Then build it up and pass it to the View. This book is great and talks about using a presentation model. With AutoMapper, think about how you would accomplish your mapping without it, then make use of it. AutoMapper isn't going to do anything magic, it eliminates keyboard slapping.
AutoMapper aside, take your list of requirments:
List of Posts [ int Id, string Body, int Likes, string p.User.FirstName, string p.User.LastName ]
List of Tags [int Id, string Name]
List of All Authors that exist on my Database [ string
UrlFriendlyName ]
and assuming you have these Model entites: Post, Tag, Author
Personally I don't like passing Model entities to my presentation in MVC or MVVM but that's me. Say we follow that here and create PostDisplay, TagDisplay, and AuthorDisplay.
Based on the View's requirements the ViewModel will look like this:
Public class IndexVM
{
Public List<PostDisplay> Posts {get; set;}
Public List<TagDisplay> Tags {get; set;}
Public List<AuthorDisplay> Authors {get; set;}
}
In this case the way the View is composed will require you to build it up:
public ActionResult Index()
{
var posts = postsRepository.Posts.ToList();
var tags = postsRepository.Tags.ToList();
var authors = postsRepository.Authors.ToList();
Mapper.CreateMap<Post, PostDisplay>();
Mapper.CreateMap<Tag, TagDisplay>();
Mapper.CreateMap<Author, AuthorDisplay>();
private var IndexVM = new IndexVM
{
Posts = Mapper.Map<List<Post>, List<PostDisplay>>(posts),
Tags = Mapper.Map<List<Tag>, List<TagDisplay>>(tags),
Authors = Mapper.Map<List<Author>, List<AuthorDisplay>>(authors)
};
return View(IndexVM);
}
So, what you end up with is a ViewModel to pass to your view that represents exactly what you want to display and isn't tightly coupled to your Domain Model. I can't think of a way to have AutoMapper map three separate result lists into one object.
To clarify, AutoMapper will map child collections so a structure like:
public class OrderItemDto{}
public class OrderDto
{
public List<OrderItemDto> OrderItems { get; set; }
}
will map to:
public class OrderItem{}
public class Order
{
public List<OrderItem> OrderItems { get; set; }
}
As long as you tell it how to map the types: OrderDto -> Order and OrderItemDto -> OrderItem.
As an alternative to including all of your lists of entities on a single viewmodel, you could use #Html.Action. Then, in your screen view:
#Html.Action("Index", "Posts")
#Html.Action("Index", "Tags")
#Html.Action("Index", "Authors")
This way, your Index / Screen view & model don't need to know about the other viewmodels. The partials are delivered by separate child action methods on separate controllers.
All of the automapper stuff still applies, but you would still map your entities to viewmodels individually. The difference is, instead of doing the mapping in HomeController.Index(), you would do it in PostsController.Index(), TagsController.Index(), and AuthorsController.Index().
Response to comment 1
public class IndexVM
{
// need not implement anything for Posts, Tags, or Authors
}
Then, implement 3 different methods on 3 different controllers. Here is one example for the PostsController. Follow the same pattern for TagsController and AuthorsController
// on PostsController
public PartialViewResult Index()
{
var posts = postsRepository.Posts.ToList();
// as mentioned, should do this in bootstrapper, not action method
Mapper.CreateMap<Post, PostModel>();
// automapper2 doesn't need source type in generic args
var postModels = Mapper.Map<List<PostModel>>(posts);
return PartialView(postModels);
}
You will have to create a corresponding partial view for this, strongly-typed as #model IEnumerable<BlogWeb.ViewModels.PostModel>. In that view, put the HTML that renders the Posts UI (move from your HomeController.Index view).
On your HomeController, just do this:
public ActionResult Index()
{
return View(new IndexVM);
}
Keep your view strongly-typed on the IndexVM
#model IEnumerable<BlogWeb.ViewModels.IndexVM>
... and then get the Posts, Tags, and Authors like so:
#Html.Action("Index", "Posts")
Response to comment 2
Bootstrapping... your Mapper.CreateMap configurations only have to happen once per app domain. This means you should do all of your CreateMap calls from Application_Start. Putting them in the controller code just creates unnecessary overhead. Sure, the maps need to be created - but not during each request.
This also helps with unit testing. If you put all of your Mapper.CreateMap calls into a single static method, you can call that method from a unit test method as well as from Global.asax Application_Start. Then in the unit test, one method can test that your CreateMap calls are set up correctly:
AutoMapperBootStrapper.CreateAllMaps();
Mapper.AssertConfigurationIsValid();
How do I pass variables to multiple partial views within a view? My idea is that every partial view will make up a different field in a form, and I plan on using dynamically created DOM objects with each partial view. So I need to pass in 3 parameters. An ID (to uniquely identify each DOM object), and its particular controller and action. How would I go about doing this in a view?
For example, I want to do something along the lines of...
#Html.Partial("_BookField", Model, 1, "book", "updateauthor")
#Html.Partial("_BookField", Model, 2, "book", "updatetitle")
#Html.Partial("_BookField", Model, 3, "book", "updatepublisher")
Is there a way to do this without adding additional attributes in the model?
Edit: After conferring with one of my coworkers, he also brought up a point that I'd like clarification on. He suggested that what I'm doing, which is introducing controller/action logic in the view is breaking the MVC concept. But things like ActionLinks, you have to put in the controller and action in an actionlink for it to be able to do something. Is what I'm trying to do considered breaking the MVC paradigm?
You use view models of course:
public class SubViewModel
{
public int Id { get; set; }
public string Book { get; set; }
public string Author { get; set; }
}
and then have your main view model different properties of this SubViewModel:
public class MyMainViewModel
{
public SubViewModel Sub1 { get; set; }
public SubViewModel Sub2 { get; set; }
public SubViewModel Sub3 { get; set; }
}
and then simply:
#Html.Partial("_BookField", Model.Sub1)
#Html.Partial("_BookField", Model.Sub2)
#Html.Partial("_BookField", Model.Sub3)
Of course it is the now the controller action responsibility to fill those view models (as always). And if you use editor/display templates your code might be even simpler, just like this:
#Html.DisplayFor(x => x.Sub1)
#Html.DisplayFor(x => x.Sub2)
#Html.DisplayFor(x => x.Sub3)
and because this strangely looks to me like a collection, well, you could use a collection:
public class MyMainViewModel
{
public SubViewModel[] Subs { get; set; }
}
and then simply:
#Html.DisplayFor(x => x.Subs)
Hi there I am hoping someone can point me in the right direction.
I want to create an mvc applicaton I have worked my way through the music store example and still am not 100% sure the correct way to do things.
Lets say I want to create an application that stores cooking receipes.
I have a 3 tables
RecipeTable
RecipeID
RecipeName
RecipeIngredients
RecipeIngredientID
RecipeID
IngredientID
Measurement
IngredientTable
IngredientID
IngredientName
All have PK & FK mappings very basic, I create a new mvc application and use the entity framework to create a new entity e.g. RecipeDB
My next step is I create a new model for each of the tables and give the properties my desired displaynames and specify required fields extra.
Do I then create a viewmodel e.g. RecipesViewModel that looks something like
public class RecipesViewModel
{
public int RecipeID { get; set; }
public string RecipeName { get; set; }
public List<RecipeIngredients> { get; set; }
}
I now create the controller (Ithink) but I am not really sure how to bind that to database entity.
I know you can call the database by doing something like RecipeEntities db = new recipeEntites(); however binding the results to the vm I am little confussed on how to do that.
Am I heading in the right direction so far?
You could use AutoMapper. It's a great tool allowing you to convert from one type to another and in your case from the model to the view model.
public ActionResult Foo()
{
RecipeDB model = _repository.GetRecipies();
RecipesViewModel viewModel = Mapper.Map<RecipeDB, RecipesViewModel>(model);
return View(viewModel);
}
or you could even define a custom action attribute (like the one I used in my sample MVC project) allowing you to simply write:
[AutoMap(typeof(RecipeDB), typeof(RecipesViewModel))]
public ActionResult Foo()
{
RecipeDB model = _repository.GetRecipies();
return View(model);
}