I have a simple application that I've loosely based off the MVC Music store used in a tutorial on asp.net that allows a user to enter details about TV shows that they are watching so they can keep track of which episode they're up to in each show.
The main entities in my application are Show:
Public class Show
{
// a few automatic properties
public int id { get; set; }
public Genre Genre { get; set; }
}
and the Genre class
Public partial class Genre
{
public int GenreId { get; set; }
public string Name { get; set; }
public List<Show> Shows { get; set; }
}
My POST edit method in my controller was generated by VS for me:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(Show show)
{
if (ModelState.IsValid)
{
db.Entry(show).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(show);
}
When I inspect db in the debugger, I can see that the Show objects (however many are in the database at the time. I seed it with two but usually add a third via the form) all have the genres I've entered but after the Edit action returns the view, the Genre is null while all the other values are updated. Why is this?
I thought perhaps the genre field was null because I wasn't instantiating them but where would I do that? I don't want a new genre created every time a Show's genre is set. I just want a show to have a genre reference so that I can eventually allow the user to select a genre and see all the shows they're following of that genre.
EDIT: Here's my Edit View. The Details view also looks very similar.
#model watchedCatalogue2.Models.Show
#{
ViewBag.Title = "Edit";
}
<h2>Edit</h2>
#using (Html.BeginForm()) {
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
<fieldset>
<legend>#Html.DisplayFor(m => m.Name)</legend>
#Html.HiddenFor(m => m.id)
<div class="editor-label">
#Html.LabelFor(m => m.Name)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Name)
#Html.ValidationMessageFor(m => m.Name)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.Genre)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Genre.Name)
#Html.ValidationMessageFor(m => m.Genre.Name)
</div>
<div class="editor-label">
#Html.Label("Number of episodes")
</div>
<div class="editor-field">
#Html.EditorFor(m => m.NoEpisodes)
#Html.ValidationMessageFor(m => m.NoEpisodes)
</div>
<div class="editor-label">
#Html.Label("Number of episodes watched")
</div>
<div class="editor-field">
#Html.EditorFor(m => m.NoEpisodesWatched)
#Html.ValidationMessageFor(m => m.NoEpisodesWatched)
</div>
<div class="editor-label">
#Html.Label("Watching State")
</div>
<div class="editor-field">
#Html.DropDownListFor(m => m.State, watchedCatalogue2.Models.Show.WatchStateItems)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.Description)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Description)
#Html.ValidationMessageFor(m => m.Description)
</div>
<p>
<input type="submit" value="Save" />
</p>
</fieldset>
Also, for good measure, db in my controller refers to my CatalogueEntities class:
namespace watchedCatalogue2.Models
{
public class CatalogueEntities : DbContext
{
public DbSet<Genre> Genres { get; set; }
public DbSet<Show> Shows { get; set; }
}
}
The problem is probably the fact that in MVC all the data is not retained/posted onto the POST method, but only those rendered as an editable element on the View and contained in the Model.
The simplest work-around will be to render it as a hidden field, as follows:
MVC 2.0 and earlier:
<%: Html.HiddenFor(m => m.GenreId) %>
Razor:
#Html.HiddenFor(m => m.GenreId)
If you use AJAX or something similar, you could also just send/pass the value as a parameter.
Also note, if you make use of the ModelState.IsValid functionality, it is possible and very probable that the Hidden fields would be rendered as null, and most probably as a problem. To remove this, which is not always advised, just add ModelState.Remove("TheKey");, in your case it is probably, ModelState.Remove("GenreID");
If I'm following the problem right, you need to render it on the form in some way for the data to be maintained, bearing in mind the web is stateless, if the value isn't present when the form is posted, it won't be bound back on to your view model.
On your view include in the form:
#Html.HiddenFor(model => model.GenreId)
Or depending on what your URL is like on your Get, you could change your POST method signature to include the id.
After some research, I noticed many of the model classes in the examples had references to other models that were marked as virtual. I figured I had nothing to lose so I modified my Show class so public Genre Genre { get; set; } now reads public virtual Genre Genre { get; set; }. Suddenly it all works. I'd appreciate if someone who knows why it works could explain it to me because all I've seen thus far have been references to lazy loading but nothing relating to my problem.
Thanks for the help, everyone.
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I have worked with .Net webforms before and now working on a MVC project.
I am working on creating a user registration page. I have no idea how its MODEL should look like.
See database diagram
User registration page:
Firstname
LastName
Email adress
Subcribe newsletter ?
Password
Choose your city
.....
I think I have to do this in this task:
STEP 1:
Populate cities dropdownList (choose your city) with data from database
STEP 2:
Insert users email address in UserEmail table and set subcribe to 0 or 1
STEP 3:
Save user registration data and EmailID (get from UserEmails table), CityID into Users table
Should I make a large MODEL , like this :
Public Class Registration Model
{
Get, set:
all USEREMAIL plugs ties
all Users plugs ties
all Cities plugs ties
}
How to start with this task in MVC?
(I know how to develop this in webforms , but MVC model confuses me)
You were on the right track.You're trying to create a view which let's users complete a registertion form, this view needs to use the user model and at the same type display a list of cities in a drop down which come from a different table in the database but are related to the user.
In MVC there's a concept called viewmodel, all that it is is a simple class which combines one or more models together.
Below I created a model called SiteUser and then another model called SiteUserViewModel which inherits from the user and gives us all the user properties PLUS an additional property we can use to populate the cities.So when we display the page, we will use the SiteUserViewModel but when we post to the controller to save the user in the database we will use SiteUser:
Models:
namespace MVCTutorial.Models
{
public class SiteUser
{
[Display(Name="First Name")]
public string FirstName { get; set; }
[Display(Name = "Last Name")]
public string LastName { get; set; }
[DataType(DataType.EmailAddress)]
public string EmailAddress { get; set; }
[Display(Name = "Subscribe To Newsletter?")]
public bool SubscribeToNewsletter { get; set; }
[DataType(DataType.Password)]
public string Password { get; set; }
[Display(Name="City")]
public int CityId { get; set; }
}
public class SiteUserViewModel : SiteUser
{
public List<SelectListItem> Cities { get; set; }
}
}
Controller:
public class SiteUserController : Controller
{
[HttpGet]
public ActionResult Index()
{
var model = new SiteUserViewModel();
//Replace this with logic that reads cities from the database
var city1 = new SelectListItem { Text = "Johannesburg", Value = "1" };
var city2 = new SelectListItem { Text = "Cape Town", Value = "2" };
model.Cities = new List<SelectListItem> { city1, city2 };
return View(model);
}
[HttpPost]
public ActionResult CreateUser(SiteUser user)
{
System.Diagnostics.Debugger.Break();
//Write the code to add user to the database
return View();
}
}
View:
#model MVCTutorial.Models.SiteUserViewModel
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Create User</title>
</head>
<body>
#using (Html.BeginForm("CreateUser", "SiteUser"))
{
#Html.ValidationSummary(true)
<fieldset>
<legend>Site User</legend>
<div class="editor-label">
#Html.LabelFor(model => model.FirstName)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.FirstName)
#Html.ValidationMessageFor(model => model.FirstName)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.LastName)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.LastName)
#Html.ValidationMessageFor(model => model.LastName)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.EmailAddress)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.EmailAddress)
#Html.ValidationMessageFor(model => model.EmailAddress)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.SubscribeToNewsletter)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.SubscribeToNewsletter)
#Html.ValidationMessageFor(model => model.SubscribeToNewsletter)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.Password)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Password)
#Html.ValidationMessageFor(model => model.Password)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.CityId)
</div>
<div class="editor-field">
#Html.DropDownList("CityId", Model.Cities, "Please select one")
</div>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
}
</body>
</html>
Result:
User Model
public class UserModel
{
public int UserId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Location { get; set; }
public IEnumerable<UserPets> UserPets { get; set; }
}
User Pets Model
public class UserPetsModel
{
public PetModel Pet{ get; set; }
public bool UserHasPet { get; set; }
}
Using these 2 models I am creating an edit page where a User can come in and edit which Pets they have.
To enable them to state which pets they have I am trying to use checkboxes.
Edit Page
#model Models.UserModel
#using (Html.BeginForm())
{
<div class="form-group">
#Html.LabelFor(model => model.FirstName)
#Model.FirstName
</div>
#foreach (var userPets in Model.UserPets)
{
#Model.Pet.AnimalName
<div>
#Html.CheckBoxFor(u => userPets .UserHasPet)
</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>
}
The problem I am having is when trying to map the UserModel back to the controller action. When I press the save button, everything on the UserModel is being mapped back to the controller apart from the UserPetsModels which I believe is due to the use of the foreach.
Is there another way in which I can display a checkbox for each UserPetModel without using a foreach or a for loop.
Yes there is. You should create EditorTemplate for your UserPetsModel. It will look like:
#model UserPetsModel
#Model.Pet.AnimalName
<div>
#Html.CheckBoxFor(model => model.UserHasPet)
</div>
And then you can simply do:
#Html.EditorFor(model => model.UserPets)
EditorFor will create right binding for you. Note that you should create EditorTemplate only for UserPets and it also will work for List<UserPetsModel> and IEnumarable<UserPetsModel> with the same syntax that i show.
I would suggest replace the loop with EditorTemplate. So your
#foreach (var userPets in Model.UserPets)
{
#Model.Pet.AnimalName
<div>
#Html.CheckBoxFor(u => userPets.UserHasPet)
</div>
}
would look like:
<div class="row">
#Html.EditorFor(m => m.UserPets)
</div>
And define a view in (~/Views/Shared/EditorTemplates/UserPets.cshtml) like:
#model UserPetsModel
#Html.HiddenFor(x => x.Pet.PetId)
#Html.LabelFor(x => x.UserHasPet, Model.Pet.AnimalName)
#Html.CheckBoxFor(x => x.UserHasPet)
I am new to ASP.NET MVC and using version 5. I created a form that is in the layout, and I cannot cannot get it to show validation errors on the view. It will post to the action correctly, and if the model is valid, it will execute. If the model is invalid I will get the following error.
I am hoping someone can point me in the right direction. Thank you in advance!
Server Error in '/' Application.
The view 'ContactSubmit' or its master was not found or no view engine supports the searched locations. The following locations were searched:
~/Views/Home/ContactSubmit.aspx
~/Views/Home/ContactSubmit.ascx
~/Views/Shared/ContactSubmit.aspx
~/Views/Shared/ContactSubmit.ascx
~/Views/Home/ContactSubmit.cshtml
~/Views/Home/ContactSubmit.vbhtml
~/Views/Shared/ContactSubmit.cshtml
~/Views/Shared/ContactSubmit.vbhtml
This is my model I am using:
public partial class Lead
{
[Key]
public int LeadId { get; set; }
[Required]
[StringLength(50, MinimumLength=2, ErrorMessage="* A valid first name is required.")]
[Display(Name="First Name")]
public string FirstName { get; set; }
[Required]
[StringLength(50, MinimumLength=2, ErrorMessage="* A valid last name is required.")]
[Display(Name="Last Name")]
public string LastName { get; set; }
[Required]
[StringLength(50, MinimumLength=2, ErrorMessage="* A valid company is required.")]
public string Company { get; set; }
[Required]
[StringLength(50)]
[EmailAddress(ErrorMessage="* A valid email address is required.")]
public string Email { get; set; }
[Required]
[StringLength(15, MinimumLength=9, ErrorMessage="* A valid phone nunber is required.")]
[Phone(ErrorMessage="Please enter a valid phone number.")]
public string Phone { get; set; }
}
This is the code I have in my Home controller:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult ContactSubmit(
[Bind(Include = "FirstName, LastName, Company, Email, Phone")]
Lead lead)
{
try
{
if (ModelState.IsValid)
{
lead.Tenant = SessionManager.Get<Tenant>(Constants.SessionTenant);
lead.Refferer = SessionManager.Get<string>(Constants.SessionRefferal);
DataStoreManager.AddLead(lead);
return RedirectToAction("SubmissionConfirmed", lead);
}
}
catch (DataException /* dex */)
{
ModelState.AddModelError("", "Unable to perform action. Please contact us.");
return RedirectToAction("SubmissionFailed", lead);
}
return View(lead);
}
[HttpGet]
public ActionResult ContactSubmit()
{
return View();
}
This is the form that I have in my layout:
#using (Html.BeginForm("ContactSubmit", "Home", FormMethod.Post))
{
#Html.AntiForgeryToken()
<fieldset>
<div class="editor-label">
#Html.LabelFor(m => m.FirstName)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.FirstName)
#Html.ValidationMessageFor(m => m.FirstName)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.LastName)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.LastName)
#Html.ValidationMessageFor(m => m.LastName)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.Company)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Company)
#Html.ValidationMessageFor(m => m.Company)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.Email)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Email)
#Html.ValidationMessageFor(m => m.Email)
</div>
<div class="editor-label">
#Html.LabelFor(m => m.Phone)
</div>
<div class="editor-field">
#Html.EditorFor(m => m.Phone)
#Html.ValidationMessageFor(m => m.Phone)
</div>
<div class="masthead-button-wrapper">
<input class="btn btn-warning" type="submit" value="Submit" />
</div>
</fieldset>
}
There is one error in your code, I didn't notice first. In the get method you are using -
return View();
Which means your view does not allow parameter but when there is an error you are using -
return View(lead);
In this case MVC is looking for the view with the same name but which also accepts a parameter of Lead type and it fails since there is no view with that option and the only one that is found does not accept parameter as seen from the Get method. When there is no error, you are redirecting to -
return RedirectToAction("SubmissionConfirmed", lead);
and the View with the parameter is never needed to be searched and thus no error.
So, change the view to accept a parameter of Lead and change your get method accordingly.
May be this would help. -
[HttpGet]
public ActionResult ContactSubmit()
{
var lead = new Lead();
return View(lead);
}
and in the view add
#model Lead
at the top
EDIT : In case since you are redirecting you should know that ModelState gets initialized in each request, so redirecting clears it automatically. You have to use some other means to pass modelstate or better if you use client side validation.
i want to to create a create-view where you have the possibility to enter a value for more than one entity - "a list of entities"
e.g. Entity Class
public class MyEntity{
public string myAttribute { get; set; }
}
For the View I created a ModelView which looks like this:
public class MoreEntites{
public List<MyEntity> MyEntities { get; set; }
}
In the View I want to use MoreEntities to give the user the possibility to enter more datasets than one in just one view (my suggestions which doesnt work of course)
#model myproject.ViewModels.MoreEntities
...
<div class="editor-label">
#Html.LabelFor(model => model.MyEntities.ElementAt(0).MyAttribute)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyEntities.ElementAt(0).MyAttribute)
#Html.ValidationMessageFor(model => model.MyEntities.ElementAt(0).MyAttribute)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.MyEntities.ElementAt(1).MyAttribute)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyEntities.ElementAt(1).MyAttribute)
#Html.ValidationMessageFor(model => model.MyEntities.ElementAt(1).MyAttribute)
</div>
...
Now in the controller I want to iterate over the list and write every item of MyEntities in the database. When I run the programm I get an exception that my List is null and I should check it for null before I use it.
Is this possible and how does it work? One "Solution" would be to create an Array but in this case my program would be scalable.
Thanks for help!
Works with Array[] of Entity!!!!
Solution:
Model:
public class MyEntity{
public string MyAttribute { get; set; }
}
ViewModel:
public class MoreEntites{
public MyEntity[] MyEntities { get; set; }
}
View:
#model myproject.ViewModels.MoreEntities
...
<div class="editor-label">
#Html.LabelFor(model => model.MyEntities[0].MyAttribute)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyEntities.[0].MyAttribute)
#Html.ValidationMessageFor(model => model.MyEntities[0].MyAttribute)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.MyEntities[1].MyAttribute)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyEntities[1].MyAttribute)
#Html.ValidationMessageFor(model => model.MyEntities[1].MyAttribute)
</div>
...
controller:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult CreateMoreEntitiesAtOnce(MoreEntities set)
{
foreach(var item in set.MyEntities)
{
db.MyEntity.Add(item);
}
db.SaveChanges();
return RedirectToAction("Index");
}
in my case if have to try if its possible to add more TextBoxes to the View by JavaScript
Therefore you need to increment the name of the textboxes in plain html when adding them to the DOM
How do i get Entity Frameworks foreign keys to pick up when I generate the view with the add view dialog.
My Models are like
public class System
{
#region Properties
public int SystemId { get; set; }
public string SystemName { get; set; }
#endregion
}
public class Module
{
#region Properties
public int ModuleId { get; set; }
//[Required]
[Display(Name="Module Name")]
public string ModuleName { get; set; }
[Display(Name="Date Added")]
public DateTime DateAdded { get; set; }
//[ForeignKey("CurrentSystem")]
public int SystemId { get; set; }
//[ForeignKey()]
//[ForeignKey("SystemId")]
public System System { get; set; }
#endregion
}
When i click on the Controller, then Add View, the modal opens. I select all the details that is needed and then the following is generated ( I did not include the entire view).
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>Module</legend>
<div class="editor-label">
#Html.LabelFor(model => model.ModuleName)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.ModuleName)
#Html.ValidationMessageFor(model => model.ModuleName)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.DateAdded)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.DateAdded)
#Html.ValidationMessageFor(model => model.DateAdded)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.SystemId)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.SystemId)
#Html.ValidationMessageFor(model => model.SystemId)
</div>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
}
I want the SystemId to be a dropdown and not a text field. How do i do this ?
Are you sure you created a class derived from dbContext with a property of type DBSet<System> and a property of type DBSet<module> ?
Provided you have, and you select a controller with the option "read and write actions with entity framework" and select both your class Module) and your context in the drop downs below that, MVC should generate the correct code view and controller code to display a combo for the system.
It worked for me in MVC4, at least. Remember to generate your project before trying to add a controller. I think MVc uses reflection so it needs an up-to-date assembly...
Use a view-model. MVC uses the data annotations to figure out how to display the properties. If you want your view to behave in a different manner than your model, you need to map your model to a view-model to handle the extra logic (ie a drop down where an int exists). Then generate your view from the view-model class.
The view-model adds a layer to deal with the seperations of concerns here. You want your view to be different than your model will allow so add a view model class that will take the model data and display it in a way that you want.