I have viewmodel which i am binding with my view call "EditProfile". Now once the user click on the "EditProfile" link from the menu bar I load all the profile information by calling get restful service and user can see his/her profile.
User can change any field they want but I want to post only fields that are changed by User.
I know how to compare two properties but don't know how to pull only modified properties from the viewmodel. Have anybody arrived to this situation before?
Properties in my viewmodel are:
public class UserViewModel
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string Profession { get; set; }
}
In the past I implemented INotifyPropertyChanged for the ViewModel. And I logged which property's changed after the PropertyChanged event fired.
Why not take an alternative approach - post everything (so the model is available) and simply have "IsDirty" properties on your objects that are smart enough to submit only changes to the database (like the entity framework does by default)
You can simply form your own jQuery .post() parameters, but unless you have a ton of data - why? It makes for a difficult to read view model (how do you know what is posted under what scenarios) so the typical approach is to post separate view models or post everything which in my opinion for basic forms is easier.
Related
I'm using entity framework and MVC (both CORE if that matters) to make a site. Using the model and tying it directly to the view is fine all the CRUD actions work, everything is lovely.
I wanted to use a couple of pages to access the model so the site looked better, so split the controls out onto separate views and added a corresponding viewmodel for each, so my project looks like this
-Model
--CustomerModel
-ViewModel
--CustomerNameVM
--CustomerAddressVM
-View
--CustomerNameView
--CustomerAddressView
The CustomerModel has a number of properties
Forename
Surname
Address
Postcode
with Forename and Surname in the CustomerNameVM and Address and Postcode in CustomerAddressVM. Surname is defined as [Required] in the model but not in CustomerNameVM which I believe is the correct way to do it.
I'm struggling to get the model loaded into the viewmodel and then trying to save it when I'm editing the address details in CustomerAddressView because it errors when I try and save as the viewmodel doesn't contain Surname (from the model), so it's null and therefore the [Required] criteria isn't being met.
I've tried a few methods of trying to get past this like :-
Jeffrey Palermo's Onion Architecture
Repositories
domain models
amongst others which all end up with the same problem, I can't save the Address as the Surname is null.
How do I ignore validation criteria for the properties of the model that aren't being referenced in the viewmodel?
Or how do I load and reference only those properties of the model that are present in viewmodel?
Edit
For those who keep asking for code, which codeset? I've tried 30 of them now, none of which do the job. Which one of these do you want? I'm trying to get a general idea of how this is supposed to work as none of the methods, documentation and associated examples function.
Here's a starter for 10, it's unlike the other 29 codesets but it's code and probably the shortest.
The controller
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Step2Address(int? id, [Bind("CustomerID,txtAddress,txtPostcode")] VMAddress VMAddress) {
if (ModelState.IsValid) {
//the saving code
}
return View(VMAddress);
}
the model
public class clsCustomer {
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int CustomerID { get; set; }
public string Forename { get; set; }
[Required]
public string Surname { get; set; }
public string Address { get; set; }
public string Postcode { get; set; }
the viewmodel
public class VMAddress {
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int CustomerID { get; set; }
public string Address { get; set; }
public string Postcode { get; set; }
}
the view
#model theProject.Models.VMStep2Contact
<form asp-action="Step2Address">
<input type="hidden" asp-for="ComplaintID" />
<input asp-for="txtAddress"/>
<input asp-for="txtPostcode"/>
<input type="submit" value="Save" />
the context
public class ContextCustomer : DbContext {
public ContextCustomer(DbContextOptions<ContextCustomer> options) : base(options) {
}
public DbSet<clsCustomer> Customer{ get; set; }
}
Clicking "Save" on the webpage calls the controller straight away, which hits the first line if (ModelState.IsValid) and as the Surname isn't set and is [Required] the ModelState is not valid so no save is attempted.
I don't actually understand what the problem is, and without code, it's impossible to say what you might be doing wrong. Generally speaking, you shouldn't have any issues since you're using view models.
A view model is, of course, not saved directly to the database, so it has to be mapped over to an actual entity class that you will be saving. In the case of an edit, you should retrieve all relevant entities from the database, map any posted values onto the appropriate properties on those entities, and then save those entities back to the database. If you're doing this, presumably, the customer model should already contain the Surname and other required properties, and you'd only be modifying/setting the address properties.
If you're doing a create, then, simply you can't just take address information. You need the name as well, so for this, you'd need to pass a view model that contains at least all required fields, such that you have all the information you need to actually save the entity.
If you're trying to do a multi-step form, where you collect all the information over multiple posts, then you simply must persist the posted data somewhere other than the database until you have enough of it to actually save an entity to the database. This is usually accomplished via Session/TempData.
I want to know if it is possible or how can I mark fields on my class used as a parameter on my Web API call to be required? I obviously can do this manually once I have received the message, but I was hoping there was something built in the pipeline (like in MVC in combination with jQuery that uses required field annotations to automatically kick back to UI showing required field notations) so I don't have to check everything manually.
Let's say I have the following ViewModel class:
public class PersonViewModel
{
public string FirstName {get; set;}
public string MiddleName {get; set;}
public string LastName {get; set;}
}
Here is my simple Post method on a PersonController
public HttpResponseMessage Post(PersonViewModel person)
{
}
Let's say the FirstName and LastName fields are required but not MiddleName. What I want to know is will the call automatically respond back to the client with a HTTP 400 Bad Request or similar if the Person object does not have one of the required fields populated?
Essentially do I have to do all of this work manually, or is there a way to have the framework handle notated fields automatically, so I don't have a lot of boilerplate validation code for required fields?
Manual Way I'm trying to avoid:
if (ModelState.IsValid)
{
if (person.LastName == string.empty)
{
return Request.CreateResponse(HttpStatusCode.BadRequest);
}
}
Any help is appreciated, thanks!
WebAPI does have a validation feature. You should be able to mark the FirstName and LastName properties as [Required] and then use the action filter at the bottom of this blog post to send back an appropriate response:
http://blogs.msdn.com/b/youssefm/archive/2012/06/28/error-handling-in-asp-net-webapi.aspx
You can read more about WebAPI validation here:
http://www.asp.net/web-api/overview/formats-and-model-binding/model-validation-in-aspnet-web-api
I have two database classes as defined below:
public class TopDate
{
[Key]
public int DateId { get; set; }
public DateTime Date { get; set; }
}
public class TopSong
{
[Key]
public int SongId { get; set; }
public string Title { get; set; }
public int DateId { get; set; }
}
where DateId is foreign key to TopSong
I am creating a controller through which i can create, delete or edit these database values.
When i right click on controller class and add controller i can only select one of the two classes defined above. Is there a way to make 1 controller to handle database updates to both these tables on one page?
Error Image:
Your controller should not be dealing directly with domain objects (meaning those things that are directly associated with your database). Create a ViewModel that contains the properties that you need, use your service layer to populate the ViewModel and your controller will use that as the Model for its base. An example of your ViewModel could be something like the following given your description above:
public class MusicViewModel
{
public int SongId {get;set;}
public string Title {get;set;}
public IEnumerable<DateTime> TopDates {get;set;}
}
This view model would contain a list of all dates that a specific song was a Top Song.
The objects you showing (code) are database classes (so called domain objects).
What you need to do is to define a view model, a standard ASP MVC practice:
you define a class, that is tailored for specific view and only containing data relevant to that particular view. So you will have a view model for a view that will create a song, another that will update it etc.
Actually situation you describing is classical situation to use view models. Using domain objects in the views, however, is really really bad practice and prone to more problems than you want to deal with.
Hope this helps.
The default strongly-typed Edit page in ASP.NET MVC 3 generally exposes all fields for the Entity. While this is often workable, some fields are a security risk. For example a simplified magazine subscription entity might look like:
public void Subscription() {
public int Id { get; set; }
public string Name { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Zip { get; set; }
public DateTime SubscribedThru { get; set; }
}
If I provide an Edit page to let users change their own address, for example, it's a security risk to include the SubscribedThru field because a knowledgeable and malicious user could give themselves a free 10-year subscription by faking the date (even if I use #Html.HiddenFor(model => model.SubscribedThru). So I am not including that field in any way on the Edit page html (via razor).
I thought the answer might be to prevent binding attempts on SubscribedThru on the Edit method in the controller using something like:
[HttpPost]
public ActionResult Edit([Bind(Exclude="SubscribedThru")] Subscription subscription) {
if (ModelState.IsValid) {
db.Entry(subscription).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
}
return View(subscription);
}
When I get to the SaveChanges(); line, it throws the error The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value. I believe that the SubscribedThru date (properly?) doesn't exist, and the empty value is less than SQL Server can handle. What surprises me is that it's even trying to update that field when I have Binding excluded for it.
So far my best solution seems to be to create a custom ViewModel that omits the SubscribedThru date, but that seems a lot of duplication of fields, validation, etc.; if possible I'd like to just make the one field SubscribedThru safe from user editing.
I can't say I fully understand the UpdateModel and TryUpdateModel methods and wonder if that's a direction to head? I played with them and EF throws errors for having duplicate objects (same key) which is perplexing.
Also, I'm not clear if the subscription data is preserved from the initial load in public ActionResult Edit(int id) in the controller all the way to the final [HttpPost]
public ActionResult Edit(Subscription subscription)... method, or does the line db.Entry(subscription).State = EntityState.Modified; try and set all the data (I thought it was just setting a flag indicating "edited-so-EF-should-save-this").
I'm a long-time .NET developer, just jumping in to my first ASP.NET MVC project, so I'm probably overlooking something painfully obvious. Thanks for any help!
So far my best solution seems to be to create a custom ViewModel that omits the SubscribedThru date, but that seems a lot of duplication of fields, validation, etc.;
That is exactly what you should do to keep things neat & tidy. AutoMapper eases the ViewModel variation headache.
This page contains an example of updating a model using TryUpdateModel (Listing 4):
http://www.asp.net/mvc/tutorials/older-versions/models-(data)/creating-model-classes-with-the-entity-framework-cs
You can whitelist only the fields that you allow to be edited, which removes the security risk.
I have a ViewModel that has been deserialized from JSON which looks something like this:
public class UserThingsUpdateViewModel
{
public IList<Thing> Things { get; set; }
[Required]
public int UserId { get; set; }
public int Age { get; set; }
}
Thing is also a ViewModel which also has various DataAnnotaion ValidationAttribute attributes on the properties.
The problem is that Lists don't seem to get validated and even after a through search I cant seem to find any articles that tackle this. Most suggest that the ViewModel is wrong if it includes a list.
So, what is the best way to validate my list and add Model Errors to the Model State?
Prior to checking ModelState.IsValid, you could add code to step through and validate each Thing, as follows:
foreach (var thing in Things)
TryValidateModel(thing);
This will validate each item, and add any errors to ModelState.
You could write a custom validator attribute and decorate the list property with it? That would allow you to write custom logic to get the elements out of the list and validate them.