I have a controller that is building a query from Linq to Sql to pass into the ViewBag.products object. The problem is, I cannot loop using a foreach on it as I expected I could.
Here's the code in the controller building the query, with the .ToList() function applied.
var products = from bundles in db.Bundle
join bProducts in db.BundleProducts on bundles.bundleId equals bProducts.bundleID
join product in db.Products on bProducts.productID equals product.productID
join images in db.Images on product.productID equals images.productID
where bundles.bundleInactiveDate > DateTime.Now
select new {
product.productName,
product.productExcerpt,
images.imageID,
images.imageURL
};
ViewBag.products = products.ToList();
Since I am using a different model on the Index.cshtml for other items needed, I thought a simple Html.Partial could be used to include the viewbag loop. I have tried it with the same result with and without using the partial and simply by using the foreach in the index.cshtml. A snippet that includes the partial is below:
<div id="bundle_products">
<!--build out individual product icons/descriptions here--->
#Html.Partial("_homeBundle")
</div>
In my _homeBundle.cshtml file I have the following:
#foreach (var item in ViewBag.products)
{
#item
}
I am getting the ViewBag data, but I am getting the entire list as output as such:
{ productName = Awesomenes Game, productExcerpt = <b>Awesome game dude!</b>, imageID = 13, imageURL = HotWallpapers.me - 008.jpg }{ productName = RPG Strategy Game, productExcerpt = <i>Test product excerpt</i>, imageID = 14, imageURL = HotWallpapers.me - 014.jpg }
What I thought I could do was:
#foreach(var item in ViewBag.Products)
{
#item.productName
}
As you can see, in the output, productName = Awesomenes Game. However, I get the error 'object' does not contain a definition for 'productName' when I attempt this.
How can I output each "field" so to say individually in my loop so I can apply the proper HTML tags and styling necessary for my page?
Do I need to make a whole new ViewModel to do this, and then create a display template as referenced here: 'object' does not contain a definition for 'X'
Or can I do what I am attempting here?
*****UPDATE*****
In my Controller I now have the following:
var bundle = db.Bundle.Where(a => a.bundleInactiveDate > DateTime.Now);
var products = from bundles in db.Bundle
join bProducts in db.BundleProducts on bundles.bundleId equals bProducts.bundleID
join product in db.Products on bProducts.productID equals product.productID
join images in db.Images on product.productID equals images.productID
where bundles.bundleInactiveDate > DateTime.Now
select new {
product.productName,
product.productExcerpt,
images.imageID,
images.imageURL
};
var bundleContainer = new FullBundleModel();
bundleContainer.bundleItems = bundle;
return View(bundleContainer);
I have a model, FullBundleModel
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace JustBundleIt.Models
{
public class FullBundleModel
{
public IQueryable<Bundles> bundleItems { get; set; }
public IQueryable<Images> imageItems { get; set; }
}
}
and my View now has
#model IEnumerable<JustBundleIt.Models.FullBundleModel>
#foreach (var item in Model)
{
<div class="hp_bundle">
<h3>#Html.Display(item.bundleName)</h3>
</div>
}
If I remove IEnumerable from the model reference, the foreach errors out that there is no public definition for an enumerator.
In the #Html.Display(item.bundleName) it errors out that the model has no definition for bundleName. If I attempt
#foreach(var item in Model.bundleItems)
I get an error that bundleItems is not defined in the model.
So what don't I have wired up correctly to use the combined model?
Do I need to make a whole new ViewModel to do this, and then create a
display template as referenced here...
Darin's answer that you linked states the important concept: Anonymous types are not intended for use across assembly boundaries and unavailable to Razor. I would add that it's rarely a good idea to expose anonymous objects outside of their immediate context.
Creating a view model specifically for view consumption is almost always the correct approach. View models can be reused across views if you are presenting similar data.
It's not necessary to create a display template, but it can be useful if you want to reuse the display logic. HTML helpers can also fill a similar function of providing reusable display logic.
Having said all of that, it's not impossible to pass an anonymous type to a view, or to read an anonymous type's members. A RouteValueDictionary can take an anonymous type (even across assemblies) and read its properties. Reflection makes it possible to read the members regardless of visibility. While this has its uses, passing data to a View is not one of them.
More reading:
Can I pass an anonymous type to my ASP.NET MVC view?
Dynamic Anonymous type in Razor causes RuntimeBinderException
Why not create a new model that contains all of the data that you need?
Example One:
public class ContainerModel
{
public IQueryable<T> modelOne;
public IQueryable<T> modelTwo;
}
This will allow you to access either of your queries in Razor:
#model SomeNamespace.ContainerModel
#foreach (var item in Model.modelOne)
{
//Do stuff
}
I personally avoid using ViewBag at all and store everything I need in such models because it's NOT dynamic and forces everything to be strongly typed. I also believe that this gives you a clearly defined structure/intent.
And just for clarity's sake:
public ViewResult Index()
{
var queryOne = from p in db.tableOne
select p;
var queryTwo = from p in db.tableTwo
select p;
var containerModel = new ContainerModel();
containerModel.modelOne = queryOne;
containerModel.modelTwo = queryTwo;
return View(containerModel);
}
Example Two:
public class ContainerModel
{
[DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")] //Format: MM/dd/yyyy (Date)
public Nullable<DateTime> startDate { get; set; }
[DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")] //Format: MM/dd/yyyy (Date)
public Nullable<DateTime> endDate { get; set; }
public SelectList dropdown { get; set; }
public IQueryable<T> modelOne { get; set; }
public IQueryable<T> modelTwo { get; set; }
}
In this case you've stored 3 other items in the model with your 2 queries. You can use the Html helpers to create a Drop Down List in Razor:
#Html.DropDownList("dropdown", Model.dropdown)
And you can use the DisplayFor helper to display your dates as defined in your model with Data Annotations:
#Html.DisplayFor(a => a.startDate)
This is advantageous IMO because it allows you to define all of the data that you want to make use of in your View AND how you plan to format that data in a single place. Your Controller contains all of the business logic, your Model contains all of the data/formatting, and your View is only concerned with the content of your page.
Related
My controller is returning following list :
public ActionResult Index()
{
CRMDataContext mycontext=new CRMDataContext();
var myquery = (from c in mycontext.Websites
select c).ToList();
return View(myquery);
}
i'm wondering how can i loop through myquery to display its properties in view??
any suggestions for improving above code will be added advantage.
#foreach(var item in Model){
...
}
improvement suggestions:
move your query in another method/class for core reusage
separate responsibilities by using separate models for domain and view
You can use foreach loop:
#{
foreach (var element in Model)
{
//Write you html code here.
}
}
First of all it's best that you map your entity into a model and use the model in your view. Most importantly if you will not be using all the fields in your entity.
Suppose your entity has this structure:
public class Website {
public string Title {get;set;}
public string Url {get;set;}
public string Description {get;set;}
}
In your view you can do something like:
#model IEnumerable<Website> // you may need to fully qualify it or add the namespace in your web.config
#foreach(var o in Model){
<div>
<h1>#o.Title</h1>
<p>#o.Description</p>
</div>
}
I am teaching myself asp .net mvc3.
I have a partial view which uses various models and lookup type db. I want to keep it strongly typed and use it in multiple places but I am not sure how to implement it.
The example below should explain it better. This question might get a bit long and I appreciate your patience.
The partial view basically gives a small description of the property. A snippet of the ‘_PropertyExcerptPartial’ is below:
#model Test.ViewModels.PropertyExcerptViewModel
<div>
<h3>#Html.DisplayFor(model => model.Property.NoOfBedrooms) bedroom #Html.DisplayFor(model => model.FurnitureType.FurnitureTypeDescription) flat to Rent </h3>
…
</div>
I want to keep this partial view strongly typed and use it in multiple places. The model that it is strongly typed to is as follows:
public class PropertyExcerptViewModel
{
public Property Property { get; set; }
public FurnitureType FurnitureType { get; set; }
}
The two 2 database that this model looks up is as follows:
public class Property
{
public int PropertyId {get; set; }
...
public int NoOfBedrooms {get; set;}
public int FurnishedType { get; set; }
...
}
public class FurnishedType
{
public int FurnishedTypeId { get; set; }
public string FurnishedTypeDescription { get; set; }
}
The furnished type database is basically just a lookup table with the following data:
1 - Furnished
2 - Not Furnished
3 - Part Furnished
4 - Negotiable
I have many such lookups in that I only store an int value in the property database which can be used to look up the description. These databases are not linked to property database and the value of furniture type is read via a function GetFurnitureType(id). I pass stored int value of Property.FurnitureType as the id.
However, I encounter a problem when I try to use this partial view as I am not sure how to pass these multiple models from a view to partial view.
Say I am trying to create an ‘added property’ page. This page basically list the properties added by the logged in user. To facilitate this, I have created another function called GetAddedProperties(userId) that return the properties added by a particular user. In the ‘added property’ view, I can call a foreach function to loop through all the properties returned by GetAddedProperties and display the _PropertyExcerptPartial. Something like this:
<div>
#foreach (var item in //Not sure what to pass here)
{
#Html.Partial("_PropertyExcerptPartial",item)
}
</div>
However, I can’t use the partial view to display information as it will display the int value of furniture type stored in the property database and I am not sure how to get the corresponding FurnitureTypeDescription and pass it to the partial view from the ‘added property’ page.
Any help would be appreciated. Thanks a lot!
You should start by designing a real view model, not some class that you suffix its name with ViewModel and stuff your domain models inside. That's not a view model.
So think of what information you need to work with in your view and design your real view model:
public class PropertyExcerptViewModel
{
public int NoOfBedrooms { get; set; }
public string FurnishedTypeDescription { get; set; }
}
and then adapt your partial to work with this view model:
#model Test.ViewModels.PropertyExcerptViewModel
<div>
<h3>
#Html.DisplayFor(model => model.NoOfBedrooms)
bedroom
#Html.DisplayFor(model => model.FurnitureTypeDescription)
flat to Rent
</h3>
...
</div>
OK, now that we have a real view model let's see how we could populate it. So basically the main view could be strongly typed to a collection of those view models:
#model IEnumerable<Test.ViewModels.PropertyExcerptViewModel>
<div>
#foreach (var item in Model)
{
#Html.Partial("_PropertyExcerptPartial", item)
}
</div>
and the last bit of course is the main controller that will do all the db querying and building of the view model that will be passed to the main view:
[Authorize]
public ActionResult SomeAction()
{
// get the currently logged in username
string user = User.Identity.Name;
// query the database in order to fetch the corresponding domain entities
IEnumerable<Property> properties = GetAddedProperties(user);
// Now let's build the view model:
IEnumerable<PropertyExcerptViewModel> vm = properties.Select(x => new PropertyExcerptViewModel
{
NoOfBedrooms = x.NoOfBedrooms,
FurnishedTypeDescription = GetFurnitureType(x.FurnishedType).FurnishedTypeDescription
});
// and finally pass the view model to the view
return View(vm);
}
Be careful with the lazy nature of EF if that is the ORM that you are using in order not to fall into the SELECT N + 1 trap.
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)
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();
I have a model which contains a list of another model.
Let's say I have a MovieModel:
public class MovieModel
{
public int MovieId { get; set; }
public string Title { get; set; }
public string Director { get; set; }
}
Then I have the RentalModel:
public class RentalModel
{
public int RentalId { get; set; }
public string CustomerId { get; set; }
public List<MovieModel> Movies { get; set; }
}
Then I have a place where all the rentals are displayed, which by clicking on the rental, its details will be displayed, from the "ShowRentals.aspx" to "ShowRentalDetails.aspx"
<% using (Html.BeginForm()) { %>
<% foreach(var rent in Model) { %>
<div class="editor-label">
<div class="editor-field">
<%: rent.RentalId %>
<%: Html.ActionLink("Details", "ShowRentalDetails",
new {rentalId = rent.RentalId,
customerId = rent.CustomerId,
movies = rent.Movies,
})%>
When I debug, I see that the Movies list is always null. This is because only primitive parameters are passed successfully, such as the Ids. I was never able to pass complex types. I really need this list to be passed on to the controller. Is it maybe because the actionlink is not capable? What other work-arounds can I do? I've been stuck on this for a while.
Nevermind the bare code here, this is just to show you what I'm doing with the list. Please help.
(follow up)
In the Controller, here's the two actions, ShowRentals and ShowRentalDetails:
public ActionResult ShowRentals()
{
MembershipUser user = Membership.GetUser(User.Identity.Name, true);
Guid guid = (Guid)user.ProviderUserKey;
Entities dataContext = new Entities();
Member member = dataContext.Members.Where(m => m.UserID == guid).First();
IEnumerable<RentalModel> toReturn = from r in member.Rentals
select new RentalModel
{
RentalId = m.RentalID,
CustomerId = m.CustomerID,
};
return View(toReturn);
}
[Authorize]
public ActionResult ShowRentalDetails(RentalModel model, List<MovieModel> movies)
{
return View("ShowRentalDetails", model);
}
I can't set it in ShowRentals because the array of movies in the database is of Movie type and not MovieModel, so the two lists are not compatible. It is null in the model when passed from ShowRentals view and the model is reconstructed by mvc, and it also doesn't work when explicitly passed from the actionlink as a parameter. help!
I believe Html.ActionLink performs a GET and you can't pass complex data types using a GET.
If you could refetch the movie list in your ShowRentDetails controller by using the rental id I think that would be best.
Otherwise, you could look up EditorFor templates. If you make an editorfor template for MovieModel and post a RentalModel to ShowRentDetails then you could get the MovieModel list that way.
See http://weblogs.asp.net/shijuvarghese/archive/2010/03/06/persisting-model-state-in-asp-net-mvc-using-html-serialize.aspx for another way.
On a side note, theres no need to make
List<MovieModel> movies
a second parameter in ShowRentDetails when it's already included in the model
Source: ASP.NET MVC - Trouble passing model in Html.ActionLink routeValues
It is clear you cant pass complex view models through action link. There is a possibility to pass simple objects which does not have any complex properties. There is another way you can do as multiple submit buttons and do a post to controller. Through the submit you have possibilities to post complex view models