Protected Variables and model binding - c#

Please see the models below:
public class Apple //: Fruit
{
public string Description { get; set; }
public int Id { get; protected set; }
}
public class AppleModel
{
public int Id { get; set; }
public string Description { get; set; }
}
and the controller below:
[HttpPost]
public ActionResult Index(Apple apple)
{
return View();
}
[HttpGet]
public ActionResult Index()
{
var AppleModel = new AppleModel();
AppleModel.Id = 1;
AppleModel.Description = "Apple";
var Apple = AutoMapper.Mapper.Map<Apple>(AppleModel);
return View("View1",Apple);
}
and the view below:
#model PreQualification.Web.Controllers.Apple
#{
ViewBag.Title = "View1";
}
<h2>View1</h2>
#using (Html.BeginForm())
{
#Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>AppleModel</h4>
<hr />
#Html.ValidationSummary(true)
<div class="form-group">
#Html.LabelFor(model => model.Id)
<div class="col-md-10">
#Html.EditorFor(model => model.Id)
#Html.ValidationMessageFor(model => model.Id)
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Description, new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Description)
#Html.ValidationMessageFor(model => model.Description)
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Save" class="btn btn-default" />
</div>
</div>
</div>
}
<div>
#Html.ActionLink("Back to List", "Index")
</div>
#section Scripts {
#Scripts.Render("~/bundles/jqueryval")
}
Apple.Id is 0 in the HttpPost method because it is a protected variable in the model. Is there anyway around this?
The reason I ask is because I am trying to use this as a model: https://github.com/nhibernate/NHibernate.AspNet.Identity/tree/master/source/NHibernate.AspNet.Identity and the id contained in the superclass is protected.

There are a couple ways around this, including a child class that implements a public whose setter applies the value to the protected id field.
However these are bandaids. Generally these problems are encountered because of a difference in how people view models. Either it is a reusable Data Transfer Object or it is not.
In the world where it is not, you have to shoehorn business objects into bindable models and always run into these weird problems.
In the world where they are, they are custom tailored to fit the data needs and are mapped into business objects with something like an automapper. More importantly, by making a model to fit this request, you protect against attacks on accidentally exposed parameters.
If the makeshift business object has public properties that change your behavior, they can be exploited by sending additional parameters back with the post request.
I know this does not specifically answer your question, but following the path where models are not DTO's is probably not the right answer either.

As elaborated by peewee_RotA, it's better to separate out the conceptual differences between a model used for a view and a domain model that will actually perform an action or is used to directly perform an action. To that end, you need a view model such as Apple
public class Apple
{
public string Description { get; set; }
public int Id { get; set; }
}
In your post action, you'd have;
[HttpPost]
public ActionResult Index(Apple apple)
{
// translate your view model to your domain model
AppleModel model = new AppleModel(apple.Id, apple.Description);
model.DoStuff();
}
In terms of NHiberhate though, it's not easy to instantiate the required object with the view model's ID and this is the crux of your issue I think. You're trying to use your domain model as a view model and the domain model is locked down...legitimately. It's job is to control how IdentityUser and the like are instantiated as they're meant to be generated by the associated factory classes, not MVC's model binder.
To that end, leave your view model as simple as possible and leverage NHibernate's factory classes to create the necessary Identity objects by looking up the ID. This link may shed some light on how to look up the user ID passed in by Apple.Id.
EDIT
I've done a little more digging on looking up the entity in NHibernate and the following post seems to do the basics. Does this get what you need?

Related

MVC Submit not editting a property of the model

I got a strange issue.
When I'm trying to edit an object in mvc, just one of the object's properties is not changing, all the other properties gets their new values.
I'm using EF with repositories and unit of work.
This is the object:
public partial class License
{
public int LicenseID { get; set; }
public string Lic_LicenseRequest { get; set; } // <-- this is the problematic property
public int Lic_LicenseMaxClientsNum { get; set; }
public string Lic_LicenseComments { get; set; }
}
This is the controller:
public ActionResult Edit(int id = 0)
{
LicenseModel model = new LicenseModel();
model.License = unit.LicenseRepository.GetObjectById(id);
if (model.License == null)
{
return HttpNotFound();
}
return View(model);
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(LicenseModel model)
{
if (ModelState.IsValid)
{
unit.LicenseRepository.EditObject(model.License);
unit.Save();
return RedirectToAction("Index");
}
LicenseModel newModel = new LicenseModel();
newModel.License = unit.LicenseRepository.GetObjectById(model.License.LicenseID);
return View(newModel);
}
This is the View:
#model MySystem.UI.MVC.Models.LicenseModel
<body>
#using (Html.BeginForm())
{
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
<fieldset>
<legend>License</legend>
#Html.HiddenFor(model => model.License.LicenseID)
<div class="form-group">
#Html.LabelFor(model => model.License.Lic_LicenseMaxClientsNum)
#Html.TextBoxFor(model => model.License.Lic_LicenseMaxClientsNum)
<p class="help-block">#Html.ValidationMessageFor(model => model.License.Lic_LicenseMaxClientsNum)</p>
</div>
<div class="form-group">
#Html.LabelFor(model => model.License.Lic_LicenseRequest)
#Html.TextBoxFor(model => model.License.Lic_LicenseRequest)
<p class="help-block">#Html.ValidationMessageFor(model => model.License.Lic_LicenseRequest)</p>
</div>
<div class="form-group">
#Html.LabelFor(model => model.License.Lic_LicenseComments)
#Html.TextAreaFor(model => model.License.Lic_LicenseComments)
<p class="help-block">#Html.ValidationMessageFor(model => model.License.Lic_LicenseComments)</p>
</div>
<p>
<button type="submit" value="Save">Save</button>
</p>
</fieldset>
}
</body>
I want to be clear that I didn't bring here all the properties for the License object beacuse it's a lot. But I use ViewModel beacuse some of the properties require dropdownlist (and I'm not usind ViewBag or ViewData).
I tried to put directly in the database a temporary string for the property, but the it doesn;t show any value at all.
I'm thinking that it might be beacuse I added this property a while after loading the db to the EF and to the VS project. I did refresh the EF of course, but it might not success.
How can I be sure that the property in the EF and project is comunating correctly with the db? What else could be the problem? (again, all the other properties are correctly modified).
Like I suspect, unfortunately the EF refresh was not successfully made, so I refresh the hole EF from the databse and it worked.
If you have used Repository and Unit Of Work patterns; one more logical step would be using EF context with a per request life time (not Session, not Application, but Request). This way you do not have to refresh EF much, which is not a good thing in a web app.
Db Context will be disposed at the end of request life time (one experience: do not call SaveChanges at that point, but at a logical point in your app; preferably in your service class).
Unity dependency injection library already has a MVC bootstrapper that will provide you control over your injected object life time.
This library implemented a generic Repository pattern alongside Unit Of Work and has a video to how put things together in a MVC app. I've used it and enjoyed it.

Form sends empty model

I have a list of Objects which I want to modify on my View, I have built a View Model to contain the list of objects:
public class TrainerListViewModel
{
public List<Trainer> Trainers { get; set; }
}
and I send a list of Trainers to the view from the controller:
public virtual ActionResult Social()
{
var Trainers = new TrainerListViewModel();
Trainers.Trainers = (from t in _db.Trainers select t).ToList();
return View(Trainers);
}
and here is my view:
#model XStreamingFitness.ViewModels.TrainerListViewModel
#using (Html.BeginForm("Social", "Participant", FormMethod.Post))
{
for (int i = 0; i < Model.Trainers.Count; i++)
{
<div class="formSep">
<div class="editor-label">
#Html.LabelFor(m => m.Trainers[i].permissionPostFacebook)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Trainers[i].permissionPostFacebook)
#Html.ValidationMessageFor(m => m.Trainers[i].permissionPostFacebook)
</div>
</div>
}
<input type="submit" value="Save Settings" name="Submit" />
}
now here is the POST controller method:
[HttpPost]
public virtual ActionResult Social(TrainerListViewModel Trainers)
{
return RedirectToAction("Profile");
}
but everytime I submit, the Trainers model is empty and I am not sure why this could be happening.
This question has been asked before here at SO I suggest you check mvc3 submit model empty, its the same principals as the problem you are having.
See the snippet from the post.
I see people writing the following lambda expression modelItem =>
item.SomeProperty in their views very often and asking why the model
binder doesn't correctly bind collection properties on their view
models.
This won't generate proper name for the checkbox so that the default
model binder is able to recreate the Settings collection. I would
recommend you reading the following blog post to better understand the
correct format that the model binder expects.
-By Darin Dimitrov
It is to do with the way you are building your form he goes to suggest you use Property Editor Templates for the Trainer object.
This should then work.
Hope it helps

Form in Partial not binding to model

I've got a page basically displaying an article backed by a database.
Below that article, there is a comments section. This is provided by a #Html.Action call returning a _Comments partial.
Within that _Comments partial. There is an optional _AddComment #Html.Action call that renders a _AddComment partial within it.
The _AddComment partial is backed by _AddComment controller methods for GET and POST.
[HttpPost]
[ValidateAntiForgeryToken()]
public ActionResult _AddComment(EditComment comment)
The GET method just returns an "EditComment" VM with the AssetID attached.
Whenever a comment is filled in and posted within the _AddComment view. It's controller method is called correctly, but the model isn't passed back.
If I look at the Request parameters I can see all the properties of the model being passed back correctly. However, it's not being bound into the Controllers method parameter.
I've tried specifying "Model" as the route params for the Html.Begin form. It's made no difference.
Have looked at a number of SO posts, none of which sort the issue I'm having!
Presumably the model binding is failing somewhere for some reason. But obviously without an exception I've no idea what's wrong!
View Model Code
public class EditComment
{
public Boolean HasRating { get; set; }
public int AssetID { get; set; }
public int CommentID { get; set; }
public int Rating { get; set; }
public string Comment { get; set; }
}
View Code
#model SEISMatch.UI.Models.Content.EditComment
<hr />
<h3><span class="colored">///</span> Leave a Comment</h3>
<div class="row" style="margin-top: 20px;">
#using (Html.BeginForm("_AddComment", "Content", Model, FormMethod.Post))
{
#Html.ValidationSummary(false)
#Html.AntiForgeryToken()
#Html.HiddenFor(m => m.AssetID)
#Html.HiddenFor(m => m.CommentID)
if (Model.HasRating)
{
#Html.EditorFor(m => m.Rating, "_StarRating")
}
<div class="span7">
#Html.TextAreaFor(m => m.Comment, new { #class = "span7", placeholder = "Comment", rows = "5" })
</div>
<div class="span7 center">
<button type="submit" class="btn btn-success">Post comment</button>
</div>
}
</div>
Your action parameter name is comment and class EditComment has Property Comment. Modelbinder gets confused.
Rename your action parameter and problem solved.
[HttpPost]
[ValidateAntiForgeryToken()]
public ActionResult _AddComment(EditComment model)

ASP.Net MVC3 missing model properties

I am new to MVC3 and am trying to write a blog application as a learning tool.
I've created a database object for the blog post and generated a controller using the Controller with Read/Write actions and views using Entity Framework to control the entity.
I'm having troubles with the edit commands. There are about 6 properties for a blog post but I only want to allow the edit to modify the title and content of the post. My code is as follows:
public ActionResult Edit(int id)
{
blog_Post blog_post = db.blog_Post.Find(id);
return View(blog_post);
}
//
// POST: /Post/Edit/5
[HttpPost]
public ActionResult Edit(blog_Post blog_post)
{
if (ModelState.IsValid)
{
db.Entry(blog_post).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(blog_post);
}
#model BlogVersion1._0.blog_Post
#{
ViewBag.Title = "Edit";
}
<h2>Edit</h2>
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>blog_Post</legend>
<div class="editor-label">
#Html.LabelFor(model => model.Title)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Title)
#Html.ValidationMessageFor(model => model.Title)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.PostContent)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.PostContent)
#Html.ValidationMessageFor(model => model.PostContent)
</div>
<p>
<input type="submit" value="Save" />
</p>
</fieldset>
}
<div>
#Html.ActionLink("Back to List", "Index")
</div>
The problem that comes about is in the public ActionResult Edit(blog_Post blog_post) method. In the Edit(int id) method, I have put a breakpoint in and I can see that blog_post is being properly passed to the view (including all of its properties populated).
But the blog_post being returned to the [HttpPost] method is missing properties for UserId, DateCreated, etc. An exception is obviously thrown on the db.SaveChanges call as required foreign keys are missing.
How do I ensure that all properties are returned to the second edit method to properly make the update?
Because you are not sending the values of those elements from your form when you do the POST ing. One way to fix this is to keep them inside the form using Hidden Variables
#using(Html.BeginForm())
{
#Html.EditorFor(model => model.Title)
#Html.HiddenFor(model => model.UserId)
<input type="submit" />
}
I think the clean solution is to "Dont use the Domain model in the view, Use a ViewModel with necessary properties for the View. In this case, obviously CreatedDate should not be something the View should supply. It should be something the code will be filled to the object.
So create a ViewModel for this
public class BlogPostViewModel
{
public int ID { set;get;}
public string Title { set;get;}
public string Description { set;get;}
}
and use this for transfering data from View to controller and viceversa
public ActionResult Edit(int id)
{
var domainObject=repo.GetPost(id);
var viewModel=new BlogPostViewModel();
viewModel.ID=domainObject.ID;
viewModel.Title=domainObject.Title;
//map other REQUIRED properties also
return View(viewModel);
}
Your view will be strongly typed to this
#model BlogPostViewModel
#using(Html.BeginForm())
{
#Html.EditorFor(model => model.Title)
#Html.HiddenFor(model => model.Description)
<input type="submit" />
}
In the POST action,map it back to the domain object and save
[HttpPost]
public ActionResult Edit(BlogPostViewModel model)
{
if(ModelState.IsValid)
{
var domainObject=new blog_Post();
domainObject.Title=model.Title;
domainObject.ModifiedDate=DateTime.Now;
//set other properties also
repo.Update(domainObject);
return RedirecToAction("Success");
}
return View(model);
}
Instead of manually mapping properties one by one you can consider using AutoMapper library which does this for you in one line of code!
Just add hidden fields for all other, non-editable properties.
#Html.HiddenFor(model => model.Id)
These field will be included in POST and hence, model binder will correctly put them into your blog_post instance.
On the other side, you should really be using view models - simple POCO classes that will be models for your views. Using entity models directly is not recommended.
Here's some info on that:
ASP.NET MVC ViewModel Pattern
http://stephenwalther.com/archive/2009/04/13/asp-net-mvc-tip-50-ndash-create-view-models.aspx
The model binder will only populate the properties that are POSTed in the HTTP request. Your view only contains Title and PostContent.
You either need to include hidden fields for each of the missing properties. Or just the ID property and then do a database lookup for the rest.
For your case, I think You should rather use the HtmlHelper extension method "EditorForModel" instead of calling "EditorFor" for each property. You are complicating your life using EditorFor on each property (and as gred84 is saying, it doesn't post the non displayed properties in the HTTP request in you context).
In your blog_Post model class you should flag each property that you don't want to be edited with the attribute [HiddenInput(DisplayValue = false)]
Then instead of all your code in the view, you can simply have (simplified - without validation summary)
#using (Html.BeginForm())
{
#Html.EditorForModel()
<input type="submit" value="Save" />
}

MVC 3 with Entity Framework and Editing Multiple Objects leads to "referential integrity constraint violation"

I have an MVC 3 project that I am working on using Entity Framework as my model. I have an object "Employer" that has "Address" and "PostalAddress" that I would like to display (view) and update (edit) at the same time (i.e. on page with employer details and address details being updated at the same time)
My view seems to work fine:
var employer = (from e in entities.Employers.Include("Address").Include("PostalAddress")
where e.EmployerNumber == employerNumber
select e).First();
return View(employer);
My edit shows up fine (i.e. all of the textboxes are populated with both employer and address details)
[HttpPost]
public ActionResult Edit(Employer employer)
{
if (ModelState.IsValid)
{
entities.Employers.Attach(employer);
entities.ObjectStateManager.ChangeObjectState(employer, EntityState.Modified);
entities.SaveChanges();
return RedirectToAction("Index");
}
return View(employer);
}
But when I go to save I get the following exception on the entities.Employers.Attach(employer) line:
A referential integrity constraint violation occurred: The property
values that define the referential constraints are not consistent
between principal and dependent objects in the relationship.
When I look at the employer object it is trying to attach it seems to have "lost" it's Address and PostalAddress items.
This is my first MVC 3 project so any help would be appreciated.
The edit page view looks like this
#model MyProject.BusinessObjects.Employer
#{ ViewBag.Title = "Edit Employer Details"; }
<h2>Edit Employer Details</h2>
#using (Html.BeginForm())
{
#Html.ValidationSummary(true)
<fieldset>
<legend>Employer</legend>
<div class="editor-label">Name</div>
<div class="editor-field">
#Html.EditorFor(model => model.Name)
#Html.ValidationMessageFor(model => model.Name)
</div>
<fieldset>
<legend>Address</legend>
<div class="editor-label">Line One</div>
<div class="editor-field">
#Html.EditorFor(model => model.Address.LineOne)
#Html.ValidationMessageFor(model => model.Address.LineOne)
</div>
<div class="editor-label">Line Two</div>
<div class="editor-field">
#Html.EditorFor(model => model.Address.LineTwo)
#Html.ValidationMessageFor(model => model.Address.LineTwo)
</div>
<div class="editor-label">Suburb</div>
<div class="editor-field">
#Html.EditorFor(model => model.Address.Suburb)
#Html.ValidationMessageFor(model => model.Address.Suburb)
</div>
<div class="editor-label">State</div>
<div class="editor-field">
#Html.EditorFor(model => model.Address.State)
#Html.ValidationMessageFor(model => model.Address.State)
</div>
<div class="editor-label">Post Code</div>
<div class="editor-field">
#Html.EditorFor(model => model.Address.PostCode)
#Html.ValidationMessageFor(model => model.Address.PostCode)
</div>
</fieldset>
<p>
<input type="submit" value="Save Changes" />
</p>
</fieldset>
}
Could you please post your razor file?
I am guessing that the modelbinding is not working properly.
How are you creating the form?
I would suggest you to use the 'ViewModel' pattern to address this issue.
Create a Class that contains the properties that are shown to the user, and in the action, get this object and 'transform' it on the model object.
Would be something like this:
Imagine you have these classes:
public class Employee{
public string Name {get; set;}
public Address Address {get; set;}
}
public class Address {
public string Street {get; set;}
}
Than your viewmodel would be:
public class EmployeeViewModel{
public string Name {get; set;}
public string Street {get; set;}
}
You can use Automapper to easily convert between those objects.
I think you are having problems with the ModelBinder.
Its probably not working with complex types for you (I'm guessing Address and PostalAddress are navigational properties of Employer).
you could try the code below.
[HttpPost]
public ActionResult Edit(Employer employer, FormCollection col)
{
if (ModelState.IsValid)
{
var emp = employer;
//populate emp.Address and emp.PostalAddress with values from col
entities.Employers.Attach(emp);
entities.ObjectStateManager.ChangeObjectState(emp, EntityState.Modified);
entities.SaveChanges();
return RedirectToAction("Index");
}
return View(employer);
}

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