I am getting stuck using a ViewModel. Suppose I want to give a logged-in person an Edit Form with only a few of the fields from my Person domain model (maybe I want to custom annotate validations in the ViewModel).
I am getting stuck in two separate places in the controller (I have marked them with "<<< >>>").
When I pass the whole Person object as a property to my ViewModel, I know what to do. I can get my code to only update the name fields, but then I have lost my ability to validate the individual properties in my ViewModel. On the hand if I limit the properties in my ViewModel to only to a few properties, then my code in the GET section where I cann vm.Person doesn't work, since I am not passing the Person.
I scanned many examples on SO, but they were all using AutoMapper. Can I accomplish this without a mapper, and/or how do I write my own? And thanks in advance!
Model:
public class Person()
{
public int PersonId { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string Email { get; set; }
}
ViewModel:
public class LoggedInPersonViewModel()
{
public int PersonId { get; set; }
[Required(ErrorMessage = "Last Name is required")]
public string LastName { get; set; }
public string FirstName { get; set; }
}
Repository:
public Person GetLoggedInPerson()
{
var user = HttpContext.Current.User.Identity;
var userid = user.GetUserId();
return db.People.SingleOrDefault(i => i.UserId == userid);
}
Controller:
public class RegistrationController : Controller
{
//Get Logged in User, Edit Form
public ActionResult UpdateDetails()
{
LoggedInPersonViewModel vm = new LoggedInPersonViewModel();
<<<Do I also need a Person property in my ViewModel>>>
vm.Person = repository.GetLoggedInPerson();
return View(vm);
}
//POST
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult UpdateDetails(LoggedInPersonViewModel loggedinpersonviewmodel)
{
if (ModelState.IsValid)
{
<<<what do i do here? is this correct? Again I cannot use Person if not in my VM.>>>
//Person person = db.People.Find(loggedinpersonviewmodel.PersonId);
//Person.FirstName = loggedinpersonviewmodel.FirstName;
//Person.LastName = loggedinpersonviewmodel.LastName;
//db.Entry(person).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index", "Person");
}
return View(loggedinpersonviewmodel);
}
}
}
Is there a way...or do I have to use AutoMapper for this?
I think you need to Map LoggedInPersonViewModel and Person. Example
public ActionResult UpdateDetails()
{
var person = repository.GetLoggedInPerson();
LoggedInPersonViewModel vm = new LoggedInPersonViewModel();
vm.PersonId = person.PersonId;
//Rest of properties
...
//return view model
return View(vm);
}
I would recommend AutoMapper this type of work. i.e. AutoMapper is a simple little library built to solve a deceptively complex problem - getting rid of code that mapped one object to another.
Related
Model:
public class Word
{
public int ID { get; set; }
public string Title { get; set; }
public DateTime? WhenCreated { get; set; }
public ApplicationUser Author { get; set; }
[NotMapped]
public string AuthorName
{
get
{
if (Author != null)
{
return Author.UserName;
}
else {
return "";
}
}
}
public List<Definition> Definitions { get; set; }
}
Controller:
[HttpGet]
public IEnumerable<Word> Get()
{
return _db.Words.Include(x=>x.Author).ToList();
}
My Controller now returns entire ApplicationUser class which is one of properties of Word. I want to send only one property of ApplicationUser: UserName. How can I do that?
I've added AuthorName, which would return only data that I want from ApplicationUser. Unfortunately I still have to .Include(x=>x.Author) to make this property work. Can I somehow omit including Author in process of data serialization (to hide it when sending data to user)?
I know I can use .Select() method, but it requires me to type all properties I will need. If I modify my Model in the future, I will need to update all those .Select() which will would be inconvenient and waste of time.
How would you solve that?
You need to create a Dto object and assign the values to it and return the Dto instead.
Dto
public class WordDto
{
public string Title { get; set; }
public DateTime? WhenCreated { get; set; }
public string AuthorName { get; set; }
}
Then in your action
[HttpGet]
public async Task<IEnumerable<WordDto>> Get()
{
return _db.Words
.Include(x=>x.Author)
.Select(x =>
new WordDto
{
Title = x.Title,
DateTime = x.WhenCreated,
AuthorName = x.Author?.UserName ?? string.Empty
}
)
.ToListAsync();
}
You can try it as shown below.
Note : You don't need to use Include here.
[HttpGet]
public async Task<IEnumerable<Word>> Get()
{
return _db.Words.Select(x => new
{
Word = x,
AuthorName = x.Author.UserName
}
).ToList();
}
Create a View model and use AutoMapper to populate. Look at using AutoMapper and ProjectTo extension https://github.com/AutoMapper/AutoMapper/wiki/Queryable-Extensions
That way if you add properties to View model they will be automatically mapped if they exist on your EF model
So create a VM with required properties named appropriately (see AutoMapper docs on naming conventions):
public class WordVM
{
public string Title { get; set; }
public DateTime? WhenCreated { get; set; }
public string AuthorUserName { get; set; }
}
Then use AutoMapper to project (it will do any required includes so if you changed the VM later then it would handle that)
_db.Words.ProjectTo<WordVM>().ToList();
You don't need the NotMapped property AutoMapper would map the navigation property Author and the Author Property UserName to AuthorUserName
My workaround was to get all the related entities with .include(), then loop over them and omit the property values I did not want to return. It would require some maintenance in case your model changed, but surprisingly, it did not impact the response time dramatically.
Okay, so i have my ViewModel and I understand what the controller does, I'm just having difficulty implementing it. I don't know how to code a controller for the ViewModel, i've tried researching it myself and can't find anything.
Here is my viewModel, how would I go about constructing the controller? Not asking you to do it for me, just how to do it
public class ViewOrderViewModel
{
//From ORDER Table
public int OrderId { get; set; }
public System.DateTime OrderDate { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string PostalCode { get; set; }
public string Country { get; set; }
public string Email { get; set; }
public decimal Total { get; set; }
//from Products
public List<Product> Products { get; set; }
}
UPDATE
public class ViewOrderController : Controller
{
// GET: ViewOrder
public ActionResult ViewOrders()
{
var order = new Order();
var viewModel = GetViewModel(order);
return View(viewModel);
}
public ViewOrderViewModel GetViewModel(Order orderObject)
{
ViewOrderViewModel viewModel = new ViewOrderViewModel();
viewModel.OrderId = orderObject.OrderId;
viewModel.OrderDate = orderObject.OrderDate;
viewModel.FirstName = orderObject.FirstName;
viewModel.LastName = orderObject.LastName;
viewModel.City = orderObject.City;
viewModel.Address = orderObject.Address;
viewModel.Country = orderObject.Country;
viewModel.Email = orderObject.Email;
viewModel.PostalCode = orderObject.PostalCode;
viewModel.Total = orderObject.Total;
return viewModel;
}
}
Still unsure about how to map the List of products in the ViewModel class to the list of products in the db
Typically, your view is going to be "bound" to the ViewModel. It's like saying "Ok, I'm the view for an 'Order' and I only need to worry about the properties that you defined in ViewOrderViewModel".
The controller is not required for that binding to happen. The binding is declared at the top of your view:
Order.cshtml
#Model MyProject.Web.ViewModels.ViewOrderViewModel
<div>
<!-- Html for the view-->
</div>
This allows you to access properties on that model within the view. Razor has some functions that make life easy. For example, if you want to display the OrderId it might look like this:
<span>OrderId: #Model.OrderId </span>
The view doesn't care what values are set for each of those properties, it only cares that the properties exist. Where the controller comes into play is populating those properties with the values you want and then passing the ViewModel to the view:
public ActionResult Order()
{
var viewModel = new ViewOrderViewModel();
// Load data into each property
viewModel.OrderId = 123; // etc..
// Return it to the view. Asp.net knows to return
// it to the Order.cshtml view because the view
// and the controller action share the same name.
return View(viewModel);
}
Edit: In response to your questions in the comments: If you need to populate your ViewModel with values from a different model (such as a database model) you can create a mapper like so:
public ViewOrderViewModel GetViewModel(Order orderObject)
{
ViewOrderViewModel viewModel = new ViewOrderViewModel();
viewModel.OrderId = orderObject.OrderId;
viewModel.FirstName = orderObject.FirstName;
// etc...
return viewModel;
}
and then in your controller you would do something like this:
// var order = new Order()
var viewModel = GetViewModel(order);
I'm trying to add a new item to an existent list in my MVC application, my problem that's I don't know the correct approach to do it.
I've done this so far:
My Customer code:
Controller
public class CustomerController : Controller
{
public CustomerBusiness customerBusiness { get; set; }
public CustomerController()
{
customerBusiness = new CustomerBusiness();
}
//Some code that makes CRUD and more these methods
[HttpGet]
public ActionResult ViewAllJobOfferts(int id)
{
var cust = customerBusiness.GetById(id);
return View(cust.JobOfferts);
}
public ActionResult CreateJobOffert(int id)
{
var cust = customerBusiness.GetById(id);
return View(cust);
}
/* [HttpPost]
public ActionResult CreateJobOffert(JobOffertModel jobOffert)
{
return View();
}*/
}
I have a relationship 1 to n between my entities Customer and JobOffert, and the method ViewAllJobOfferts works fine, but I got stuck when I try to add a new JobOffert.
I have a couple of questions, here we go:
I must to create a controller special to JobOfferts, or control
inside the CustomerController?
When I try to create the view that will submit the form to new
JobOffert I didn't know how to link the customer to this new
JobOffert, f I try create a page using customer model, I do not have the JobOffert attributes and if I create using the JobOffert model, I dont know how make the link between these two objects. how must I do this?
PS.: Here the code of both models:
JobOffert Model
Customer Model
I must to create a controller special to JobOfferts, or control inside
the CustomerController?
Not necessarily, controller like other class should follow SRP (Single Responsibility Principle). In this case as long as CustomerController facilitating information related to Customer, it's completely fine.
When I try to create the view that will submit the form to new JobOffert I didn't know how to link the customer to this new JobOffert, f I try create a page using customer model, I do not have the JobOffert attributes and if I create using the JobOffert model, I dont know how make the link between these two objects. how must I do this?
The link between the customer and JobOffer is as you defined One-to-Many and entities contains references to each other. E.g. You can find all JobOffer for a customer whose Id is 1024 by querying JobOffer table where customerID = 1024. Likewise each JobOffer is traceable by Customer reference in entity class.
Now about creating a new JobOffer for a customer this is how you can go about:
public class CustomerController : Controller
{
public CustomerBusiness customerBusiness { get; set; }
public CustomerController()
{
customerBusiness = new CustomerBusiness();
}
//Some code that makes CRUD and more these methods
[HttpGet]
public ActionResult ViewAllJobOffersForCustomer(int customerId)
{
ICollection<JobOfferModel> model = customerBusiness.GetAllJobOffersByCustomerId(customerId);
return View(model);
}
[HttpGet]
public ActionResult CreateJobOffer()
{
// Blank model object to accept values from user,
// you may like to create a view model based on UI needs.
JobOfferModel jobOfferModel = new JobOfferModel();
return View(jobOfferModel);
}
[HttpPost]
public ActionResult CreateJobOffer(JobOfferModel jobOffer)
{
// You get a filled object here that contains customer id and job offer details
customerBusiness.CreateJobOffer(jobOffer);
return RedirectToAction("ViewAllJobOffersForCustomer", new { customerId = jobOffer.CustomerId });
}
Sample business service class:
public class CustomerBusiness
{
public ICollection<JobOfferModel> GetAllJobOffersByCustomerId(int customerId)
{
// TODO: Fetch job offer details from persistent store
// E.g.
// dataContext.JobOffers.Where(x => x.CustomerId == customerId).ToList();
throw new NotImplementedException();
}
public void CreateJobOffer(JobOfferModel jobOffer)
{
// TODO: Add job offer details in persistent store
// E.g.
// dataContext.JobOffers.Add(jobOffer);
}
}
Modified entity classes:
public class JobOfferModel
{
[Key]
public int Id { get; set; }
public string Description { get; set; }
[Required]
[DefaultValue(false)]
public bool Acepted { get; set; }
[Required]
[DefaultValue(true)]
public bool Active { get; set; }
[Required]
[Column(TypeName = "DateTime2")]
public DateTime JobDate { get; set; }
[ForeignKey("Id")]
public int CustomerId { get; set; }
public virtual CustomerModel Customer { get; set; }
}
public class CustomerModel
{
[Key]
public int Id { get; set; }
[Required]
public string Name { get; set; }
[Column(TypeName = "DateTime2")]
public DateTime BirthDate { get; set; }
public int PhoneNumber { get; set; }
public ICollection<JobOfferModel> JobOffert { get; set; }
}
So basically you will have a method in CustomerController that returns empty ViewModel or Model object. On view you will make customerId hidden. So that when form is posted it is mapped to correct customer along with JobOffer details. Once you have model object in HttpPost method you just need to insert an entry in JobOffer table (any persistent store) with customerId associated with it.
There are other nitty gritty but above typical approach will give you a good start I hope. Cheers
I defined a model like this
public class Planilla
{
[Key]
public int IDPlanilla { get; set; }
[Required(ErrorMessage = "*")]
[Display(Name = "Dirección de Negocio")]
public int IDDireccionDeNegocio { get; set; }
[Required (ErrorMessage = "*")]
public string Nombre { get; set; }
[Display(Name = "Descripción")]
public string Descripcion { get; set; }
public bool Activo { get; set; }
[ScriptIgnore]
public virtual DireccionDeNegocio DireccionDeNegocio { get; set; }
}
And I have a method in my controller that returns the first element of this model
[HttpPost]
public ActionResult GetElements(string IDCampana)
{
Planilla query = db.Planillas.First();
return Json(query);
}
My problem is when I invoke this method from client side throws an error that say's
circular reference is detected trying to serialize
System.Data.Entity.DynamicProxies.Planilla_7F7D4D6D9AD7AEDCC59865F32D5D02B4023989FC7178D7698895D2CA59F26FEE
Debugging my code I realized that the object returned by the execution
of the methodFirstit's a
{System.Data.Entity.DynamicProxies.Planilla_7F7D4D6D9AD7AEDCC59865F32D5D02B4023989FC7178D7698895D2CA59F26FEE}
instead a Model of my namespace like
Example.Models.DireccionDeNegocio`.
Why am I doing wrong?? Because I tried with other models and work's well
Use view models, that's the only advice I can give you. Never pass domain models to your views. It's as simple as that. And if you respect this simple rule and fundamental rule in ASP.NET MVC applications you will never have problems. So for example if you need only the id and the description in your view:
[HttpPost]
public ActionResult GetElements(string IDCampana)
{
Planilla query = db.Planillas.First();
return Json(new
{
Id = query.IDPlanilla,
Description = query.Description
});
}
Notice that in this case the anonymous object serves as view model. But if you really wanted to do things properly you would write your view model:
public class PlanillaViewModel
{
public int Id { get; set; }
public string Description { get; set; }
}
and then:
[HttpPost]
public ActionResult GetElements(string IDCampana)
{
Planilla query = db.Planillas.First();
return Json(new PlanillaViewModel
{
Id = query.IDPlanilla,
Description = query.Description
});
}
By the way Ayende wrote a nice series of blog posts about this.
System.Data.Entity.DynamicProxies.* is the Entity Framework proxy namespace. Your DbContext creates your entities as such to support lazy loading and change tracking. This isn't your problem. The problem likely lies in a circular association.
I am coverting my app from webforms to mvc, at the moment i am at a design issue (well i just dont know how to do it in mvc).
Basically my model would be something like this:
public class DamagedItem
{
public Int32 LoanId {get;set;}
public String IdentityCode {get;set;}
public virtual ICollection<DamagedItems> DamagedItems {get;set;}
}
In my controller i would like to do:
public ActionResult Add(DamagedItem damagedItem)
{
//Do update logic here
}
Then in my view i can add to the ICollection as needed.
But, i can't do this because if i try and access the ICollection from my controller it is null.
Here is an image of when i want to do:
I just dont know how to lay it out in my view, how to i add such items to my ICollection, update the view then when i need to save i have access to what i have added from my controller?
Thanks,
Nick
Edit:
I was thinking of using a partial in the view and doing all the logic for the bottom half using ajax and storing it in a session variable, but i would prefer NOT to make it reliant on ajax.
It is better to separate: you shoud have 2 actions, which produce 2 view.
You should have LoadInformationModel classe:
public class LoadInformationModel
{
public string StudentCode { get; set; }
public string FirstName { get; set; }
// etc..
public ICollection<Damage> Type { get; set; }
}
corresponding action
[HttpGet]
public ActionResult LoanInformation(int id)
{
var loanInfo = // get data by given id..
var model = new LoadInformationModel {
StudentCode = loanInfo.StudentCode,
// etc
Type = new List<Damage> { new Damage { Value = "Damaged"}, new Damage { Value = "Damaged Again" }
}
return View(model);
}
As well as RepairDataModel class
public class RepairDataModel
{
public bool CoveredByWarranty { get; set; }
public ICollection Status { get; set; }
}
And corresponding action
[HttpGet]
public ActionResult Repair(int id)
{
// logic
return View(model);
}
Your task is to create Post handler, that would save data to DB then form submitted
[HttpPost]
public ActionResult(RepairDataModel model)
{
// save to db
return View();
}
The view returned by Index() method, could be created like
#Html.RenderAction("LoanInformation")
#Html.RenderAction("Repair")
The rest depends on your desing and imagination. I hope that would give you direction.
What I can see is only the DamagedItem lacks a contructor with values for Collection;
public class DamagedItem
{
public DamagedItem()
{
DamagedItems = new List<DamagedItems>();
DamagedItems.Add(new DamagedItem { Description = "Damaged" } );
}
public Int32 LoanId {get;set;}
public String IdentityCode {get;set;}
public virtual ICollection<DamagedItems> DamagedItems {get;set;}
}