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How to edit multiple models in a single Razor View
I'm using MVC3 to make an order functionality. I have Order and OrderDetail Model. Order and OrderDetail is in an one to many relationship.
The two models look something like this:
public class order
{
public int OrderId{get;set;}
public int OrderStatusID { get; set; }
public virtual OrderStatus OrderStatus { get; set; }
public virtual ICollection<OrderDetail> OrderDetails { get; set; }
}
public class OrderDetail
{
public int OrderDetailID { get; set; }
public int OrderID { get; set; }
public int Quantity { get; set; }
public string Description { get; set; }
public int CategoryID { get; set; }
public virtual Order Order { get; set; }
public virtual Category Category { get; set; }
}
I want to use them both in a view, so I made the OrderViewModel for it below,
public class OrderViewModel
{
public virtual Order Order { get;set; }
public virtual List<OrderDetail> OrderDetails { get;set; }
}
I have two questions:
1, How can I use the OrderViewModel to make pages for creating and editing Order?
I made the partial view for the OrderDetail. In the Creating page, I did something like the following, but I don't think it's correct.
#foreach (var detail in Model.OrderDetails)
{
#Html.Partial("_OrderDetail", detail)
}
2, Order and OrderDetail is in an one to many relationship, in the creating Order page, I want users to be able to add multiple OrderDetail. I used jQuery to make a button that can make multiple OrderDetail fields, but I don't know how to Retrieve the values from every OrderDetail.
How is this done?
Use EditorFor for the details.
Please have a look of below link and see an answer of Darin Dimitrov
How to use LabelFor on a strongly typed view for a list
LabelFor not working in loop (for/foreach/template)
Do let me know if you still have any query.
Related
Note: These classes are related, but not part of the same Aggregate (like PurchaseOrder and OrderLine) - so I do not have a navigation property from "One" to "Many".
=== Entities ===
public class One
{
public Guid Id { get; set; }
public string Name { get; set; }
}
public class Many
{
public Guid Id { get; set; }
public string Name { get; set; }
public Guid One { get; set; }
}
=== Contracts ===
public class OneWithMany
{
public Guid Id { get; set; }
public string Name { get; set; }
public IEnumerable<Many>? ManyRelatedObjects { get; set; }
}
I want to select all One objects and any related Many objects from DbSet/DbSet into OneWithMany.
To ensure I don't miss properties added in future I am using ProjectTo in AutoMapper - but I can't work out how to fit it into the equation.
Unfortunately, it seems Entity Framework does not support GroupJoin.
The solution is to do the projection and as much filtering as possible as two separate queries, and then combine them into a result in memory.
If you find EF related answers on the web related to GroupJoin make sure you check the example code to see if they are actually showing code working on arrays instead of DbSet.
I've been following the contoso university tutorial on Microsoft´s site and I have some doubts about how the Entity Framework is doing some stuff. Here we go...
On the beginning of the tutorial, we created three classes that will be turned into tables in my database.
I´d like to know when and how entity instantiates my classes to populate the objects.
Im using code-first approach.
Example:
The classes im using:
public class Course
{
public int CourseID { get; set; }
public string Title { get; set; }
public int Credits { get; set; }
public virtual ICollection<Enrollment> Enrollments { get; set; }
}
public class Enrollment
{
public int EnrollmentID { get; set; }
public int CourseID { get; set; }
public int StudentID { get; set; }
public decimal? Grade { get; set; }
public virtual Course Course { get; set; }
public virtual Student Student { get; set; }
}
public class Student
{
public int StudentID { get; set; }
public string LastName { get; set; }
public string FirstMidName { get; set; }
public DateTime EnrollmentDate { get; set; }
public virtual ICollection<Enrollment> Enrollments { get; set; }
}
After following the tutorial I can now list all my Students and theirs respectives Course(s), as well as their properties in enrollments lists.
When did entity instantiated my Student classes and populated it with the respective Enrollment(s) lists?
How does it know what enrollments are linked to that student?
I dont see any new constructor() ever beeing called.
This might be simple but Im kinda lost here.
Thanks
It doesn't instantiate anything ahead of time, and it doesn't have to. And there won't be anything in the table representing the virtual property as such, either.
These virtual properties are used by EF at runtime to store navigation information, and the collections can be null or contain 0 or more elements. There's no magic, it's just by design that EF "new"s up the collection when it needs to.
If you want to be explicit about it, you can create a constructor on your POCO as well and set your collection equal to a new hashtable.
I'm trying to create some complex form scheme in a .NET MVC 3 project (or so I think). I'll show a wireframe so that you can understand better.
As you can see from the pic above, it's a form to create a new Car Dealership. I can choose from many available car's manufacturers (in the Add a tab), and each selection creates a new tab in the panel underneath it. In each panel there's a html fieldset, and I can add some new cars on it.
In the end, I want to submit all the form, which comprehends the data from the dealership (e.g. name), the car's brands that it has and the cars available for each brand. How can I do it with MVC 3? I don't know how exactly should I instantiate the model Car Dealership and its respective View. What should the cars in the panels be? An array of inputs? And how can I separate the inputs from one tab from the ones of another? All of this, using Razor!
My real-world scenario is a little bit more complicated, but I'll start by this so that I can try to solve the rest by myself. I'm using jQuery/jQuery UI, but I'm opened to other javascript alternatives (like Backbone, etc - I just don't know them yet). Thanks in advance!
UPDATE (1):
These are my models so far:
public class CarDealership
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<ManufactorOnDealership> ManufactorsOnDealership { get; set; }
}
public class Manufactor
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<ManufactorOnDealership> DealershipsOfManufactor { get; set; }
}
// Junction class: I believe it's needed because the list of Cars belongs to this relationship
public class ManufactorOnDealership
{
public int Id { get; set; }
public int CarDealershipId { get; set; }
public int ManufactorId { get; set; }
public virtual CarDealership CarDealership { get; set; }
public virtual Manufactor Manufactor { get; set; }
public virtual ICollection<Car> CarsOnDealership { get; set; }
}
public class Car
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<ManufactorOnDealership> Manufactors { get; set; }
}
So I decided to go with the code first/DbContext approach, but already have an existing database file. Nothing complex, so I am thinking I can just create the DbContext derived container class with DbSets for the respective POCO's, create the connection string to my database and I should be set. However I believe I am having difficulties properly declaring the properties in my entity classes since I am getting errors when trying access an object through the navigational properties. Usually telling me Object reference not set to an instance of an object when I try context.Products.Find(1).Category.CATNAME; etc. Also tried declaring the collection properties with virtual keyword to no avail.
Some specifics of the database schema are:
In Categories table the PCATID is a foreign key to the CategoryID in
the same Categories table and can be null.
Both CategoryID and RootCategoryID in Products table can be null and
are both foreign keys to CategoryID in the Categories table.
I am testing things at the moment but will be setting a lot of the fields to non null types eventually.
Here are my entity POCO's and the entity Dbset container class:
public class Category
{
[Key]
public int CategoryID { get; set; }
public string CATNAME { get; set; }
public int PCATID { get; set; }
public ICollection<Category> Categories { get; set; }
public ICollection<Product> Products { get; set; }
}
public class Product
{
[Key]
public int ProductID { get; set; }
public int CategoryID { get; set; }
public int RootCategoryID { get; set; }
public string Name { get; set; }
public string ShortDescription { get; set; }
public string LongDescription { get; set; }
public string Keywords { get; set; }
public decimal ListPrice { get; set; }
public Category Category { get; set; }
}
public class EFDbContext: DbContext
{
public DbSet<Product> Products { get; set; }
public DbSet<Category> Categories { get; set; }
}
You need to make PCATID a nullable property as you have said it can be null. Make all those navigation properties and collection properties virtual. EF will not be able to detect the category hierarchy so you have use either attributes or fluent API to configure that.
public class Category
{
[Key]
public int CategoryID { get; set; }
public string CATNAME { get; set; }
[ForeignKey("ParentCategory")]
public int? PCATID { get; set; }
[InverseProperty("Categories")]
public virtual Category ParentCategory { get; set; }
[InverseProperty("ParentCategory")]
public virtual ICollection<Category> Categories { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
Requirements for Creating POCO Proxies
Everything looks ready for POCO but Lazy Loading isn't sorted out at this point. By default LL is on, but in order to enable lazy loading, the Category property must be Virtual (a proxy is created that catches the reference and loads the data). If you don't want lazy loading then disable it in your EFDbContext constructor.
So your options are:
public virtual Category Category { get; set; }
or
public class EFDbContext: DbContext
{
public static EFDbContext()
{
LazyLoadingEnabled = false
}
...
}
You'd probably want to do the first one...
Are you certain you really want to use Code First? Or do you just want to use DbContext and DbSet? You can get the same benefits with Database First, using DbContext and DbSet. Since you already have a database, it's generally a lot simpler.
See: http://blogs.msdn.com/b/adonet/archive/2011/03/15/ef-4-1-model-amp-database-first-walkthrough.aspx
The only difference between Code First and Database First with DbContext is that Code first uses the fluent mapping model, while Database First uses an .edmx file. Maintaining the .edmx is much easier with an existing database.
If you're bound and determined to use Code First, then I suggest getting the Entity Framework Power Tools CTP1 and reverse engineering your database to Code First.
I agree with #Eranga about class Category (+1 to #Eranga).
public class Category {
[Key]
public int CategoryID { get; set; }
public string CATNAME { get; set; }
[ForeignKey("ParentCategory")]
public int? PCATID { get; set; }
[InverseProperty("Categories")]
public virtual Category ParentCategory { get; set; }
[InverseProperty("ParentCategory")]
public virtual ICollection<Category> Categories { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
And you also have problem with your Linq query:
context.Products.Find(1).Category.CATNAME;
EF return data only from tables that you request with Include or you use this tables in functions.
With this code all work:
db.Products
.Include(p => p.Category) // here I demand to load data from Category table
.First(p => p.ProductID == 3)
.Category
.CATNAME;
I'm having trouble passing view information from my Get/Create action to my view. Here are my three model classes;
public class Competition
{
public int Id { get; set; }
public int CompetitionId { get; set; }
public string Name { get; set; }
public string Prize { get; set; }
}
public class CompetitionEntry
{
public int Id { get; set; }
public int CompetitionEntryId { get; set; }
public string Name { get; set; }
public string Email { get; set; }
public int CompetitionId { get; set; }
}
public class CompetitionEntryViewModel
{
public int Id { get; set; }
public Competition Competitions { get; set; }
public int CompetitionId { get; set; }
public string Name { get; set; }
public string Email { get; set; }
}
Here is my Get/Create action in CompetitionEntry Controller;
public ActionResult Create(int id)
{
CompetitionEntryViewModel competitionentryviewmodel = db.CompetitionEntriesView.Find(id);
return View(competitionentryviewmodel);
}
I know this doesn't work. The id parameter goes into the URL fine. How to I get access to my Competition class in th Get action? I need to be able to show the competion name on my Create Competition entry view.
Thanks in advance!
public ActionResult Create(int id)
{
var data = db.CompetitionEntriesView.Find(id);
CompetitionEntryViewModel competitionentryviewmodel = new CompetitionEntryViewModel();
competitionentryviewmodel.CompetitionName = data.Name;
return View(competitionentryviewmodel);
}
What you are trying to do is build an object graph and display it through a view model. In order to do this, you need to map your domain model(s) to your view model.
You can do the mapping yourself by writing a lot of code (re-inventing the wheel), or, you could consider using third party tools to do this for you. I recommend you use an AutoMapper as it is very simple to use imo.
The other problem is that your view model contains a domain model. This is likely to cause you a lot of headache in near future. If I were you, I would replace Competition with CompetitionViewModel.
I would also consider creating a view model for a list of competitions, i.e. CompetitionsViewModel. Look into partial views to see how you can display a list of competitions.
Good luck