Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 6 years ago.
Improve this question
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:
Related
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 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.
I'll try to be clear. I'm developing a web application based on MVC 4 and Entity Framework. Through this app, I can create some Products which is depending on an other table which is Product Types As you can see, in my create product View, I have a dropdownlist which contains the product types :
#model BuSIMaterial.Models.Product
#{
ViewBag.Title = "Create";
}
<h2>
Create</h2>
#using (Html.BeginForm())
{
#Html.ValidationSummary(true)
<fieldset>
<legend>Product</legend>
<div class="editor-label">
Purchase date :
</div>
<div class="editor-field">
#Html.TextBoxFor(model => model.PurchaseDate, new { #class = "datepicker"})
#Html.ValidationMessageFor(model => model.PurchaseDate)
</div>
<div class="editor-label">
Serial number :
</div>
<div class="editor-field">
#Html.TextBoxFor(model => model.SerialNumber, new { maxlength = 50 })
#Html.ValidationMessageFor(model => model.SerialNumber)
</div>
<div class="editor-label">
Product type :
</div>
<div class="editor-field">
#Html.DropDownList("Id_ProductType", String.Empty)<a href="../ProductType/Create">Add
a new product type?</a>
#Html.ValidationMessageFor(model => model.Id_ProductType)
</div>
<div class="form-actions">
<button type="submit" class="btn btn-primary">Create</button>
</div>
</fieldset>
}
And in my create product type View, I have a dropdownlist of existing product companies (so the same relation which exists between product and product type :
#model BuSIMaterial.Models.ProductType
#{
ViewBag.Title = "Create";
}
<h2>Create</h2>
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>ProductType</legend>
<div class="editor-label">
Model :
</div>
<div class="editor-field">
#Html.TextBoxFor(model => model.Model, new { maxlength = 50 })
#Html.ValidationMessageFor(model => model.Model)
</div>
<div class="editor-label">
Catalog Price :
</div>
<div class="editor-field">
#Html.EditorFor(model => model.CatalogPrice)
#Html.ValidationMessageFor(model => model.CatalogPrice)
</div>
<div class="editor-label">
Company :
</div>
<div class="editor-field">
#Html.DropDownList("Id_ProductCompany", String.Empty)<a href ="../ProductCompany/Create" >Add a new company?</a>
#Html.ValidationMessageFor(model => model.Id_ProductCompany)
</div>
<div class="form-actions">
<button type="submit" class="btn btn-primary">Create</button>
</div>
</fieldset>
}
What I tried is to "mix" these 2 views in one Create Product View. So I think my action will change a little bit. Also, I think I'll have to do 2 adds in my database. Is it the best way to do what I want?
UPDATE : by using a viewmodel, I got this :
My View Model :
public class ProductViewModel
{
[Required]
public Product Product { get; set; }
[Required]
public ProductType ProductType { get; set; }
}
My Create Action :
[HttpPost]
public ActionResult CreateFullProduct(ProductViewModel pvm)
{
ViewBag.Id_ProductCompany = new SelectList(db.ProductCompanies, "Id_ProductCompany", "Name", pvm.ProductType.Id_ProductCompany);
if (ModelState.IsValid)
{
Product product = new Product { PurchaseDate = pvm.Product.PurchaseDate,
SerialNumber = pvm.Product.SerialNumber,
Id_ProductType = pvm.ProductType.Id_ProductType};
ProductType productType = new ProductType {Model = pvm.ProductType.Model,
CatalogPrice = pvm.ProductType.CatalogPrice,
Id_ProductCompany = pvm.ProductType.Id_ProductCompany};
db.ProductTypes.AddObject(productType);
db.Products.AddObject(product);
db.SaveChanges();
return RedirectToAction("Index", "Person");
}
return View(pvm);
}
When I try to save the new entries, I got this issue : The INSERT statement conflicted with the FOREIGN KEY constraint "FK_bm_ProductTypes_bm_ProductCompanies".
As Products are "dependent" on ProductTypes, merging them into one is a good idea. You'll have to merge the post action too, which will have 2 inserts into your database (which is correct, one for Product, one for ProductType.
You'll have to put them both in one Model too so you can use it in your view, something like:
public class ProductViewModel
{
public Product Product { get; set; }
public ProductType ProductType { get; set; }
}
EDIT: Your problem with your saving is because the ProductComany is not being posted (as indiciated in Chat)
To fix that, first we'll put the values for the Dropdown in the model:
public class ProductViewModel
{
public Product Product { get; set; }
public ProductType ProductType { get; set; }
public List<SelectListItem> ProductCompanies { get; set; }
}
Then populate it in your HttpGet and HttpPost by doing:
model.ProductCompanies = db.ProductCompanies
.ToList()
.Select(s => new SelectListItem
{
Text = s.Name,
Value = s.Id.ToString()
})
.ToList();
Then in your view you can do:
#Html.DropDownListFor(m => m.ProductType.Id_ProductCompany, Model.ProductCompanies)
I am using asp.net mvc 4
Is there a way to update the form based on selection made by the user?
(in this case I want to fill in address fields if something is picked from the dropdown list, otherwise a new address would need to be typed in)
My model:
public class NewCompanyModel
{
[Required]
public string CompanyName { get; set; }
public bool IsSameDayRequired { get; set; }
public int AddressID { get; set; }
public Address RegisterOfficeAddress { get; set; }
}
View:
#model ViewModels.NewCompanyModel
#using (Html.BeginForm(null, null, FormMethod.Post, new { name = "frm", id = "frm" }))
{
#Html.ValidationSummary(true)
<fieldset id="test">
<legend>Company</legend>
<h2>Register office address</h2>
<div class="editor-label">
#Html.LabelFor(model => model.AddressID)
</div>
<div class="editor-field">
#Html.DropDownListFor(model => model.AddressID, (IList<SelectListItem>)ViewBag.Addresses, new {id = "address", onchange = "window.location.href='/wizard/Address?value=' + this.value;" })
</div>
<div class="editor-label">
#Html.LabelFor(model => model.RegisterOfficeAddress.BuildingNameOrNumber)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.RegisterOfficeAddress.BuildingNameOrNumber)
#Html.ValidationMessageFor(model => model.RegisterOfficeAddress.BuildingNameOrNumber)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.RegisterOfficeAddress.StreetName)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.RegisterOfficeAddress.StreetName)
#Html.ValidationMessageFor(model => model.RegisterOfficeAddress.StreetName)
</div>
and controller:
public ActionResult Address(string value)
{
//get the address from db and somehow update the view
}
The question is how do you update the 'model.RegisterOfficeAddress.StreetName' etc
Just to make clear this is just part of the form so I cannot submit it just yet.
Many thanks
Thanks for your help; I have decided to take a different approach:
On dropdown change I submit the form:
<div class="editor-label">
#Html.LabelFor(model => model.ServiceAddress.AddressID)
</div>
<div class="editor-field">
#Html.DropDownListFor(model => model.ServiceAddress.AddressID, (IEnumerable<SelectListItem>)ViewBag.Addresses, new { onchange = "this.form.submit();" })
#Html.ValidationMessageFor(model => model.ServiceAddress.AddressID)
</div>
and then in controller:
[HttpPost]
public ActionResult NewDirector(NewDirectorVM vm, string value)
{
ModelState.Clear();
if (vm.ServiceAddress.AddressID > 0)
{
//Updates the properties of the viewModel
vm.ServiceAddress = _Repository.GetAddress(vm.ServiceAddress.AddressID);
}
return View("NewDirector", vm);
}
Please notice ModelState.Clear(); which actually allows the view to be updated from the controller (otherwise all the changes made the the viewModel by the controller would have been overwritten by the values in the view).
Common way in such cases is to update other fields via javascript:
$('##Html.IdFor(model => model.AddressID)').on('change',function(){
$.get(...,function(data){
$('##Html.IdFor(model => model.RegisterOfficeAddress.BuildingNameOrNumber)').val(data)
})
})
I am working on creating a blog with ASP.Net 4, MVC 3, Razor and C#.
There are 2 seperate tables. 1 for the actual blog post and a relationship table for categories.
The categories displays as a dropdown.
I want to add the ability to add a new category using Ajax so the user does not lose what they have already entered into the form.
What would be the best way to accomplish this?
Here is what I have right now.
Controller Code
public ActionResult Create()
{
ViewBag.category_id = new SelectList(_db.Categories, "id", "category_name");
return View();
}
Razor View
#model NPP.Models.News
#{
ViewBag.Title = "Create News Item";
}
<h2>Create News Item</h2>
<script src="#Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="#Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>News</legend>
<div class="editor-label">
#Html.LabelFor(model => model.news_title, "Title")
</div>
<div class="editor-field">
#Html.EditorFor(model => model.news_title)
#Html.ValidationMessageFor(model => model.news_title)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.news_content, "Content")
</div>
<div class="editor-field">
#Html.TextAreaFor(model => model.news_content)
#Html.ValidationMessageFor(model => model.news_content)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.news_teaser, "Teaser (optional)")
</div>
<div class="editor-field">
#Html.TextAreaFor(model => model.news_teaser)
#Html.ValidationMessageFor(model => model.news_teaser)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.category_id, "Category")
</div>
<div class="editor-field">
#Html.DropDownList("category_id", String.Empty)
#Html.ValidationMessageFor(model => model.category_id)
</div>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
}
<div>
#Html.ActionLink("Back to List", "Index")
</div>
Thanks for any help in advance. My layout page includes jquery which I would prefer to use.
Add another controler method to return you a list of categories, something like:
public JsonResult Categories()
{
return Json(DB.GetCategorys(), JsonRequestBehavior.AllowGet);
}
Then on the client side, use ajax to get your categories and bind them to your drop down, something like:
$.ajax({
url: 'http://myserver/myapp/mycontroller/Categories',
success: function(data) {
$('#dropCategorys').html('');
$.each(data, function(i, e) {
$('#dropCategorys').append('<option value="' +
e.category_id + '">' + e.category_name + '</option>');
}
}
});
This won't save your current selected item, but you can always check that before clearing the list, and reset it afterwards.
Creating the Category separately via AJAX is not your only option. You could then have a view model like this:
public class CategoryViewModel
{
public string name { get; set; }
public int id { get; set; }
}
public class CreateNewsViewModel
{
public string news_title { get; set; }
public string news_content { get; set; }
public string news_teaser { get; set; }
public string CategoryViewModel category { get; set; }
}
Change your view at the category field:
<div class="editor-label">
#Html.LabelFor(model => model.category, "Category")
</div>
<div class="editor-field">
#Html.DropDownListFor(model => model.category.id, ViewBag.category_id)
#Html.EditorFor(model => model.category.name) <!-- only show when creating a new category -->
#Html.ValidationMessageFor(model => model.category)
</div>
Then your action would look something like this:
[HttpPost, ActionName("Create")]
public ActionResult DoCreate(CreateNewsViewModel model)
{
if (ModelState.IsValid)
{
if (model.category.id == 0)
{
// create your new category using model.category.name
}
// create an entity from the model and save to your database
return RedirectToAction("Index", "News"); // do whatever you wish when you're done
}
return View("Create", model); // show Create view again if validation failed
}
This is more or less off the top of my head so let me know if I bollocks'ed any parts up.