I have the folowing class and controller (mvc)
UI Model inherits DB model (ef4.0)
public class RegistrationModel : Model.User
{
[Required]
public string PasswordText { get; set; }
}
MVC controller
public ActionResult Create(RegistrationModel registrationModel)
{
try
{
Context ctx = new Context();
Model.User user = new Model.User();
user = (registrationModel as Model.User);
user.Password = System.Text.ASCIIEncoding.ASCII.GetBytes(registrationModel.PasswordText); //do encryption later on
...
ctx.Customer.Add(registrationModel as Model.User);
ctx.SaveChanges();
}
}
when i cast the registrationmodel to a user the type remains registrationmodel is there a way to cast it, without copying all its properties to a new user object?
Model.User user = new Model.User();
user.Active = registrationModel.Active;
user.Blocked = registrationModel.Blocked;
//...
....
How about using AutoMapper. Brilliant for automatically mapping data from models to view models and so on.
correct. I had the same issue. it seems that all types of casting (document in MSDN here: http://msdn.microsoft.com/en-us/library/ms173105.aspx) does not seem to work in MVC controllers.
for instance:
// IRREGULAR MVC CONTROLLERS BEHAVIOR
// implicit casting
Model.User user = registrationModelInstance // won't case to base
// explicit casting
Model.User user = (Model.User)registrationModelInstance // won't case to base
i ended up using AutoMapper (similar to User-Defined conversion per MSDN). should look like that:
Mapper.CreateMap<RegistrationModel, Model.User>();
Mapper.Map<RegistrationModel, Model.User>(registrationModelInstance);
Related
I've been looking at some of the answers on this site about saving model data to session but none seem to work for me, or most likely I am not understanding it correctly and not sure how to implement it.
This is the latest solution I've been trying.
c# - How to save object to session in ASP.NET
In the Index I get an error on declaring the model telling me User doesn't exist
Model
public class User
{
public int Id { get; set; }
public string Username { get; set; }
public string Password { get; set; }
}
Controller
public ActionResult Index()
{
using (DefaultConnection db = new DefaultConnection())
{
var model = from u in db.Users select u;
var vm = (User)Session["User"];
return View(vm);
}
}
View
#model User
#Model.Username
I am not quite sure what you are trying to achieve here. But i can see some problems in your code
var vm = (User)Session["User"];
You are trying to access a session variable with key User and trying to cast it to a User instance. That means, Before executing this code, you should be setting a valid user object to Session["User"]. If you do not do that, your casting will fail(code will crash) because Session does not have any item for the key "User"
If you haven't set it yet, Before accessing this session object, you should set a valid User object to session.
var us = new User { Id=1, Username="test"};
Session["User"] = us;
Later, before accessing from session item, you should always check whether it is null or not
User u = null;
if(Session["User"]!=null)
{
u = Session["User"] as User;
// you may use u now.
}
Also, you are querying from the Users table and selecting the records to the variable model. But you are not using that anywhere in your code. I am not sure why you want to do that.
I am not sure why you are using session. If you are trying to pass data between your action method to view, there are other better solutions like using a viewmodel (preferred), ViewBag etc.
Remember Session data is available across the entire application for the current session., not just one page. Use it wisely.
In order to save your model to the Session, you need to set the session object first e.g.
using (DefaultConnection db = new DefaultConnection())
{
var model = from u in db.Users select u;
Session["User"] = model; //Part where you set / save into the session
var vm = Session["User"] as User; //Part where you retrieve into the session
return View(vm);
}
User user = Session["User"] as User;
if ( user == null) user = new User();
If you want to access your ViewModel on the view, you can do it in many ways one way is to associate your view to a model (known as strongly typed views). You can do this in your view:
#model type #*Associate your view to a ViewModel, where type is your ViewModel Class*#
<h1>#Model.Name</h1> #*access the properties of your view using #Model *#
#model is used to associate a model to a view while #Model is used to access the associated model of a view. I suggest you read first on how ASP.NET MVC works. You may visit the ASP.NET MVC tutorial on views
This question already has answers here:
Where to convert business model to view model?
(3 answers)
Closed 5 years ago.
I'm using MVC 4 with the repository pattern and unit testing also. I have a typical controller that has simple CRUD functionality. I've separated my View Models from my DTOs and I would like to know the best way to convert between the 2:
Models:
I have Admin.Models.Product which is my view model and AdminAssembly.Models.Product which is my DTO.
Controller:
//repo that handles product operations
AdminAssembly.Interfaces.IEntityRepository<AdminAssembly.Models.Product> db;
//default constructor
public ProductController() { db = new AdminAssembly.Repositories.EntityRepo<AdminAssembly.Models.Product>(new AdminAssembly.Models.EntitiesContext()); }
//unit testing constructor
public ProductController(AdminAssembly.Interfaces.IEntityRepository<AdminAssembly.Models.Product> context) { db = context; }
//
// POST: /Product/Create
[HttpPost]
public ActionResult Create(Admin.Models.Product product) {
if (ModelState.IsValid) {
//COMPILE-ERROR: how to convert to DTO?
db.Add(product);
}
return View();
}
//
// GET: /Product/Edit/5
public ActionResult Edit(int id) {
//COMPILE-ERROR: how to convert to view model?
Admin.Models.Product product = db.GetAll().Where(p => p.ID == id);
return View(product);
}
How do I convert between the 2?
Do I reference my DTO assembly in my view model and do something like: (won't this break my unit testing?)
//convert to AdminAssembly.Models.Product
db.Add(product.ToDTO());
//convert back to Admin.Models.Product via constructor
Admin.Models.Product product = Admin.Models.new Product(db.GetAll().Where(p => p.ID == id));
Do I need some sort of object conversion black box?
Converter.ToViewProduct(product);
Some sort of interface?
or something else?
Update 1:
public static class Product {
public static Admin.Models.Product ToView(AdminAssembly.Models.Product dto) {
Admin.Models.Product viewProduct = new Admin.Models.Product();
//straight copy
viewProduct.Property1 = dto.Property1;
viewProduct.Property2 = dto.Property2;
return viewProduct;
}
public static AdminAssembly.Models.Product ToDTO(Admin.Models.Product viewModel) {
AdminAssembly.Models.Product dtoProduct = new AdminAssembly.Models.Product();
//straight copy
dtoProduct.Property1 = viewModel.Property1;
dtoProduct.Property2 = viewModel.Property2;
//perhaps a bit of wizza-majig
dtoProduct.Property1 = viewModel.Property1 + viewModel.Property2;
return dtoProduct;
}
}
The long-hand response
[HttpPost]
public ActionResult Create(Admin.Models.Product product)
{
if (ModelState.IsValid)
{
//COMPILE-ERROR: how to convert to DTO?
var dtoProduct = new AdminAssembly.Models.Product();
dtoProduct.Property1 = product.Property1;
dtoProduct.Property2 = product.Property2;
//...and so on
db.Add(dtoProduct);
}
return View();
}
While this looks verbose and tedious (and it is) it has to happen eventually, somewhere.
You can hide this mapping either in another class or extension method, or you can use a third party like AutoMapper, as Charlino points out.
As a side note, having two classes with the same name in two different namespaces will eventually get confusing (if not for you, then for the next person who has to maintain your code.) Implement friendlier and more descriptive names wherever possible. For example, put all your view models in a folder called ViewModels, not Models. And append all your view models with ViewModel, or VM. It's also a good convention, imo, to name your view models based on the view that they are for, not so much the domain model that they will be mapped to, as not all view models will map directly to a domain model. Sometimes you'll want parts of more than one domain model, for a single view, and that will blow up your naming convention.
So in this particular case I would suggest changing Admin.Models to Admin.ViewModels and then rename the view model version of Product to CreateViewModel. Your code will be much more readable and will not be littered with namespaces throughout your methods.
All of that would result in a method that would look more like this:
[HttpPost]
public ActionResult Create(CreateViewModel viewModel)
{
if (ModelState.IsValid)
{
var product = new Product();
product.Property1 = viewModel.Property1;
product.Property2 = viewModel.Property2;
//...and so on
db.Add(product);
}
return View();
}
Check out a library called AutoMapper.
From their wiki:
What is AutoMapper?
AutoMapper is a simple little library built to solve a deceptively complex problem - getting rid of code that mapped one object to another. This type of code is rather dreary and boring to write, so why not invent a tool to do it for us?
If you dont want to use AutoMapper you may use extensions, as suggested by #Forty-Two. If the number of things to map is no very great, I would go with this approach, just because then, AutoMapper == YAGNI
public static class Extensions
{
public static ViewModel ToViewModel(this Model )
{
var vm = new ViewModel()
{
//map
};
return vm;
}
public static Model ToModel(this ViewModel viewModel)
{
var model = new Model()
{
//map
};
return model;
}
}
Similar to your code in UPDATE, but using extensions instead.
Looking for ideas to guard against malicious data changes: userA manipulating (editing or deleting) data that belongs to userB. Since we are creating entities on the client, we need to assign them (or at least some of them) to the authenticated user.
For example:
var newItem = ds.createNewItem();
newItem.OwnerId(22); //this is the problem that I see.
newItem.Name("New Item");
newItem.Description("I just changed your item!");
... //and so on
ds.saveChanges();
Assuming we know the identity of the user calling SaveChanges on our API, how do we validate our entities (new or modified) against this user?
The first thought that comes to mind is to subclass EFContextProvider, override BeforeSaveEntity and examine the entities OwnerId property against the identity of our user. For example:
if (entityInfo.Entity.GetType() == typeof(Item)
&& (entityInfo.EntityState == EntityState.Added
|| entityInfo.EntityState == EntityState.Modified)
&& ((Item)entityInfo.Entity).OwnerId != _currentUserId) {
return false
... //and so on
If using this approach, does it make sense to establish _currentUserId in the constructor of our new EFContextProvider class?
An ideas or perhaps a better way to approach this problem?
I think you are on the right track. I've been noodling this myself and have gone down much the same path.
Let's assume you've handled authentication and there's an IPrincipal available. You've got yourself a custom IIdentity too (call it AppIdentity) where you can stash the UserId for the authenticated user.
The Web Api's base ApiController class makes the ambient IPrincipal available via its User property. We will leverage that in your custom Breeze Web Api controller which might begin like this:
[Authorize]
[JsonFormatter, ODataActionFilter]
public class BreezeApiController : ApiController
{
private readonly AppContextProvider _context;
public BreezeApiController() {
// pass 'User' IPrincipal to the context ctor
_context = new AppContextProvider(User);
}
...
// one of the Query action methods
[HttpGet]
public IQueryable<Foo> Foos() {
return _context.Foos
}
...
Your custom EFContextProvider might begin like this:
public class AppContextProvider : EFContextProvider<AppDbContext>
{
public AppContextProvider(IPrincipal user)
{
UserId = ((AppIdentity) user.Identity).UserId;
}
public int UserId { get; private set; }
...
Now you probably want to prevent UserB's entities from being seen by UserA. So instead of allowing every Foo to go out the door, your custom EFContextProvider could filter accordingly.
public DbQuery Foos
{
get
{
// Here the 'Context' is your EF DbContext
return (DbQuery) Context.Foos
.Where(f => f.UserId == UserId);
}
}
Looking back at the controller, we see that its Foos GET action method is oblivious to the filter ... as it should be. We want our controllers to be light and move the business logic to the custom EFContextProvider and its helpers.
Finally, a highly simplified, general purpose BeforeSaveEntity could look like this:
private bool BeforeSaveEntity(EntityInfo info)
{
var entity = info.Entity;
if (info.EntityState == EntityState.Added)
{
entity.UserId = UserId;
return true;
}
return UserId == entity.UserId || throwCannotSaveEntityForThisUser();
}
...
private bool throwCannotSaveEntityForThisUser()
{
throw new SecurityException("Unauthorized user");
}
Notice that the custom context provider on the server is responsible for setting the UserId of added entities. We wouldn't trust the client to do that anyway. And of course it is responsible for verifying the UserId of modified and deleted entities.
Hope this helps. Remember, this is only a sketch. The real deal would have greater sophistication and be refactored into helpers.
I've implemented a base controller for my MVC 3 project to allow a common way of accessing a user entity from my db context :
public abstract class MyBaseController : Controller
{
protected DBEntitiesContainer db;
protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
base.Initialize(requestContext);
this.db = new DBEntitiesContainer();
}
public UserDetails GetActiveUserDetails()
{
UserDetails userDetails = GetObjects.GetActiveUserDetails(this.db);
return userDetails;
}
}
This works great and all my controllers have access to this.db.MyEntity and can retrieve a UserDetails object by calling this.GetActiveUserDetails()
However, the problem arises when I try to perform an update on the entity thus :
public class UpdateController : MyBaseController
{
public ActionResult Index()
{
UserDetails userDetails = this.GetActiveUserDetails();
userDetails.LastOnline = DateTime.Now;
UpdateModel(userDetails);
this.db.SaveChanges();
}
}
Any ideas why the UserDetails object is easily retrieved, but when I check my database after calling SaveChanges(), nothing has been updated ? I'm presuming I'm accessing my context in two different ways, but I can't see how I am...!
Edit: Here's the GetObjects.GetActiveUserDetails() method
public static UserDetails GetActiveUserDetails(DBEntitiesContainer db)
{
MembershipUser membershipUser = Membership.GetUser();
UserDetails userDetails;
try
{
if (membershipUser != null)
{
userDetails = (from u in db.UserDetails
where (u.UserId == (System.Guid)membershipUser.ProviderUserKey)
select u).First();
}
else
{
return GetGuestAccount();
}
}
catch
{
return GetGuestAccount();
}
return userDetails;
}
Not the cleanest method I know...
UpdateModel is helper method for Controller base class. it supports updating the properties of an object we pass it using the incoming form parameters during HttpPost action method.
It uses relfection to find out the property names of the object (Model object what we passed) and then automatically converts the assigns values to them based on the input values submitted by the form ( client form).
In your case you when u use update model it has no input value find associated model and it make the model default values as it is in database.
try to comment the updatemodel line and runt he code... it must work.
It's not a good idea to setup data access this way. One reason is that you should dispose of the db context after you use it. This means that using your method, this leaves the database connection open until garbage collection occurs, which could be minutes or hours later. As other web requests come in, new database connections are created, and again those are not disposed of either.. etc.. etc.. it's a pseudo-memory leak (not a true memory leak because it will eventually get collected, but it means resources are being used well after they are needed)
There is a field in our database which really ought to be a boolean, but for some reason the original developers made it a CHAR which will either be set to "1" or "0".
[Column("CHARGEABLE")]
[StringLength(1)]
private string Chargeable { get; set; }
I want my model to represent this field as a boolean so I figured I could add a property to my model to wrap it:
[NotMapped]
public bool ChargeableTrue
{
get
{
return Chargeable == "1" ? true : false;
}
set
{
Chargeable = value ? "1" : "0";
}
}
Now on my View I just display the EditorFor ( ChargeableTrue ), but when I click save it doesn't actually update it.
I think what is happening is that when the model is being updated, it's still attempting to get the value of 'Chargeable' from the View, even though I haven't displayed it there. And since there is no input field, it just gets null and ends up saving that to the database.
if (ModelState.IsValid)
{
db.Entry(call).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
What is one expected to do in this situation?
Based on KMan's answer, here's the extended version just in case you're not familiar with creating view models.
The idea is that your domain object is not really what you want to be updating exactly from your views. Instead, you create a go-between that can also include view-specific items (like a list of objects to populate a drop-down).
public class MyViewModel {
public bool Chargeable { get; set; }
}
Now you can do this:
#* In view *#
Html.EditorFor(m => m.Chargeable)
// In controller
public ActionResult Save(MyViewModel model) {
if (ModelState.IsValid) {
var domainObject = new MyObject() {
Chargeable = model.Chargeable ? "1" : "0"
};
// the rest of your code using domainObject
}
}
I'd consider just creating an overload of your domain object's constructor that accepts your view model to keep the mapping in one place. I typically use a tool like AutoMapper to map objects or manual extension methods.
A view model typically contains a sub-set of your domain object's properties, but can contain all of them or more properties like lists, visbility states, etc. They come in incredibly useful and I've never done a MVC project where I haven't used them.
Use a view model and make your mapping on the controller.