In MVC3, it seems that the default way to show properties of a model in your view is like so:
#Html.DisplayFor(model => model.Title)
This works fine if your model matches your object exactly. But if you define a custom ViewModel, for example like in the NerdDinner tutorial
public class DinnerFormViewModel {
// Properties
public Dinner Dinner { get; private set; }
public SelectList Countries { get; private set; }
// Constructor
public DinnerFormViewModel(Dinner dinner) {
Dinner = dinner;
Countries = new SelectList(PhoneValidator.AllCountries, dinner.Country);
}
}
Then your DisplayFor code would look like:
#Html.DisplayFor(model => model.Dinner.Title)
Which means the names of the form items are Dinner.Title instead of just Title, so if you call UpdateModel in your Action code, MVC won't "see" the properties it needs to see to update your Dinner class.
Is there a standard way of dealing with ViewModels that I'm overlooking for this scenario in MVC3?
Use the 'prefix' parameter for UpdateModel method
UpdateModel(model.Dinner, "Dinner");
and if you need to update a specified properties only - use something like this
UpdateModel(model.Dinner, "Dinner", new []{"Title"});
Related
I'm trying to do that:
Create a Model, add it on a session and send it to the view.
Change Model fields on my view
Get the Model from session updated on my controller
The problem is that my model is never updated when I'm changing values on textboxes, I'm sure that I'm missing something with razor,
View:
#model MvcTestApp.Models.Car
<div class="b1">
<div class="b2">#Html.EditorFor(e => e.KM)</div>
<div class="b2">#Html.EditorFor(e => e.RegistrationNumber)</div>
</div>
#Html.ActionLink("Car", "sendCar")
Controller:
On SendCar, I would like to get the model updated.
namespace MvcTestApp.Controllers
{
public class CarController : Controller
{
public ActionResult Show()
{
var model = new MvcTestApp.Models.Car()
{
RegistrationNumber ="12345",
KM = "12345"
};
Session["temp"] = model;
return View("Show",Session["temp"]);
}
public ActionResult sendCar()
{
return View("Show", Session["temp"]);
}
}
}
Model:
namespace MvcTestApp.Models
{
public class Car
{
[DataType(DataType.Text)]
public string KM { get; set;}
[DataType(DataType.Text)]
public string RegistrationNumber { get; set;}
}
}
You need to make your sendCar controller to update the model. Currently, all the changes you do will only persist locally until you navigate away from the page. You need to post the changed model back to the server.
Take a look at the "Handling edits" part of this example to see how it can be done:
Asp.net tutorials
The way to do this is by wrapping your model details in a form with a submit function. Then in your sendCar method take in a Car object and the model binding will take care of setting everything on the new object.
If you're wanting to persist this (I assume this is just for testing purposes?) then perhaps make your car that you're returning in your show method a class variable.
You should read a beginner tutorial about ASP.NET MVC, which will explain you how to send data from a form to a controller, as it seems you are absolutely not aware of how to do this.
You are not missing 'something', you are missing all about sending data from forms to controllers.
How can i send two Model from controller to view using same action
Let's assume your two models are instances of MyModel and MyOtherModel.
I can think of two options:
Pass MyModel as the Model and put MyOtherModel in the ViewBag.
Create class MyBigModel with a property containing MyModel and another property containing MyOtherModel and pass MyBigModel as the Model.
Option 1 is really not your ideal solution. Since your model should relate to your view (that's why I prefer the name ViewModel), I'd really go for option 2.
Option 2 would look like this:
public class MyBigModel
{
public MyModel { get; set; }
public MyOtherModel { get; set; }
}
Use ViewModel - create one more model that would contain both of the models, and send that to view
public class MyCustomViewModel
{
public MyFirstModel First { get; set; }
public MySecondModel Second { get; set; }
}
And in controller
public ActionResult Action()
{
MyFirstModel first = new MyFirstModel();
MySecondModel second = new MySecondModel();
MyCustomViewModel model = new MyCustomViewModel();
model.First = first;
model.Second = second;
return View(model);
}
Generally, as the name suggests, you should be using custom ViewModel for every view in your application, and then use tools like AutoMapper to map those view models back and forth to domain models. View models give you great flexibility in composing your view, as you can give any shape and form to them without changing domain.
I have a constants values such as "Required","Optional", and "Hidden". I want this to bind in the dropdownlist. So far on what I've done is the below code, this is coded in the view. What is the best way to bind the constant values to the dropdownlist? I want to implement this in the controller and call it in the view.
#{
var dropdownList = new List<KeyValuePair<int, string>> { new KeyValuePair<int, string>(0, "Required"), new KeyValuePair<int, string>(1, "Optional"), new KeyValuePair<int, string>(2, "Hidden") };
var selectList = new SelectList(dropdownList, "key", "value", 0);
}
Bind the selectList in the Dropdownlist
#Html.DropDownListFor(model => model.EM_ReqTitle, selectList)
Judging by the property EM_RegTitle I'm guessing that the model you're using is auto-generated from a database in some way. Maybe Entity Framework? If this is the case, then you should be able to create a partial class in the same namespace as your ORM/Entity Framework entities and add extra properties. Something like:
public partial class MyModel
{
public SelectList MyConstantValues { get; set; }
}
You can then pass your SelectList with the rest of the model.
There are usually hangups from using ORM/EF entities through every layer in your MVC app and although it looks easy in code examples online, I would recommend creating your own View Model classes and using something like AutoMapper to fill these views. This way you're only passing the data that the views need and you avoid passing the DB row, which could contain other sensitive information that you do not want the user to view or change.
You can also move the logic to generate your static value Select Lists into your domain model, or into a service class to help keep reduce the amount of code and clutter in the controllers.
Hope this helps you in some way!
Example...
Your View Model (put this in your "Model" dir):
public class MyViewModel
{
public SelectList RegTitleSelectList { get; set; }
public int RegTitle { get; set; }
}
Your Controller (goes in the "Controllers" dir):
public class SimpleController : Controller
{
MyViewModel model = new MyViewModel();
model.RegTitle = myEfModelLoadedFromTheDb.EM_RegTitle;
model.RegTitleSelectList = // Code goes here to populate the select list.
return View(model);
}
Now right click the SimpleController class name in your editor and select "Add View...".
Create a new view, tick strongly typed and select your MyViewModel class as the model class.
Now edit the view and do something similar to what you were doing earlier in your code. You'll notice there should now be a #model line at the top of your view. This indicates that your view is a strongly typed view and uses the MyViewModel model.
If you get stuck, there are plenty of examples online to getting to basics with MVC and Strongly Typed Views.
You would prefer view model and populate it with data in controller.
class MyViewModel
{
public string ReqTitle { get; set; }
public SelectList SelectListItems { get; set; }
}
Then you can use:
#Html.DropDownListFor(model => model.EM_ReqTitle, model.SelectListItems)
Alright guys, Need some help!
Im working with asp.net mvc3 razor (and am fairly new to it but did lots of web forms)
Okay so onto the problem
My question revolves around submitting a view.
I have a very complicated model that my view is based off (strongly typed).
I want to return the model into the arguments in the HttpPost method of the controller. do basically:
public ActionResult Personal()
{
DataModel dataModel = new DataModel();
FormModel model = new FormModel();
model.candidateModel = dataModel.candidateModel;
model.lookupModel = new LookupModel();
return View(model);
}
[HttpPost]
public ActionResult Personal(FormModel formModel)
{
if (ModelState.IsValid)
{
//stuff
}
return View(formModel);
}
Now...
I'm having trouble getting values into the formModel parameter on the post method.
This works (meaning i can see the value)but is tedious as i have to write exactly where it sits in a string every single field:
#Html.TextBox("formModel.candidateModel.tblApplicant.FirstName", Model.candidateModel.tblApplicant.FirstName)
It renders like this:
<input name="formModel.candidateModel.tblApplicant.FirstName" id="formModel_candidateModel_tblApplicant_FirstName" type="text" value="Graeme"/>
This doesn't work:
#Html.TextBoxFor(c => c.candidateModel.tblApplicant.FirstName)
It renders like this:
<input name="candidateModel.tblApplicant.FirstName" id="candidateModel_tblApplicant_FirstName" type="text" value="Graeme"/>
Now I'm assuming the problem lies in the discrepancy of the id's
So please answer me this:
Am i going about this the right way
Why doesn't textboxfor get the right value/id, and how do i make it get the right value/id so i can retrieve it in a POST(if that is even the problem)?
Additionally, it seems that textboxfor is restrictive, in the manner that if you have a date time, how do you use the .toshortdate() method? This makes me think textboxfor isn't useful for me.
Quick clarification:
when i say textboxfor isn't working, it IS getting values when i GET the form. So they fill, but on the POST / submission, i can't see them in the formModel in the parameters.
Another side note:
None of the html helpers work, this is the problem. They aren't appearing in modelstate either.
Thanks everyone for the help
Answer:
html.TextBoxFor and html.Textbox, POSTing values, model in parameters
It was a problem in my view somewhere, i replaced all the code with the snippet in this answer and it worked.
Thank you again
Am i going about this the right way
Yes.
Why doesn't textboxfor get the right value/id, and how do i make it get the right value/id so i can retrieve it in a POST(if that is even the problem)?
There is something else in your code that makes this not work. It's difficult to say since you haven't shown all your code. Here's a full working example which illustrates and proves that there's something else going on with your code:
Model:
public class FormModel
{
public CandidateModel candidateModel { get; set; }
}
public class CandidateModel
{
public Applicant tblApplicant { get; set; }
}
public class Applicant
{
public string FirstName { get; set; }
}
Controller:
public class HomeController : Controller
{
public ActionResult Index()
{
return View(new FormModel
{
candidateModel = new CandidateModel
{
tblApplicant = new Applicant
{
FirstName = "fn"
}
}
});
}
[HttpPost]
public ActionResult Index(FormModel formModel)
{
// the username will be correctly bound here
return View(formModel);
}
}
View:
#model FormModel
#using (Html.BeginForm())
{
#Html.EditorFor(c => c.candidateModel.tblApplicant.FirstName)
<button type="submit">OK</button>
}
Additionally, it seems that textboxfor is restrictive, in the manner
that if you have a date time, how do you use the .toshortdate()
method? This makes me think textboxfor isn't useful for me.
I agree that TextBoxFor is restrictive. That's why I would recommend you always using EditorFor instead of TextBoxFor. It will allow you to simply decorate your view model property with the [DisplayFormat] attribute and voilà. You get any format you like.
For example:
public class MyViewModel
{
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
public DateTime CreatedAt { get; set; }
}
and in the view:
#model MyViewModel
#Html.EditorFor(x => x.CreatedAt)
will format the date exactly as you expect.
the model binder uses the name to bind the values to the model, and the html helpers e.g. Html.TextBoxFor uses the body of the lambda expression to set the name, however you can specify the name yourself which you are doing by using the Html.TextBox( helper
#Html.TextBoxFor(x=>x.candidateModel.tblApplicant.FirstName),
new{#Name="formModel.candidateModel.tblApplicant.FirstName"})
If your view is strongly typed, try the helper bellow, instead call each helper on each property
#Html.EditorForModel()
#Html.EditorFor(m => m.candidateModel)
#Html.EditorFor(m => m.lookupModel)
Update:
Well, have tried to use viewmodel to simplify this task? And when you get back the data you can map your real models. keep your views clean will give you less headaches in the future. Additionally you could use AutoMapper to help you.
Here a example if you think that will help you.
http://weblogs.asp.net/shijuvarghese/archive/2010/02/01/view-model-pattern-and-automapper-in-asp-net-mvc-applications.aspx
How do I pass variables to multiple partial views within a view? My idea is that every partial view will make up a different field in a form, and I plan on using dynamically created DOM objects with each partial view. So I need to pass in 3 parameters. An ID (to uniquely identify each DOM object), and its particular controller and action. How would I go about doing this in a view?
For example, I want to do something along the lines of...
#Html.Partial("_BookField", Model, 1, "book", "updateauthor")
#Html.Partial("_BookField", Model, 2, "book", "updatetitle")
#Html.Partial("_BookField", Model, 3, "book", "updatepublisher")
Is there a way to do this without adding additional attributes in the model?
Edit: After conferring with one of my coworkers, he also brought up a point that I'd like clarification on. He suggested that what I'm doing, which is introducing controller/action logic in the view is breaking the MVC concept. But things like ActionLinks, you have to put in the controller and action in an actionlink for it to be able to do something. Is what I'm trying to do considered breaking the MVC paradigm?
You use view models of course:
public class SubViewModel
{
public int Id { get; set; }
public string Book { get; set; }
public string Author { get; set; }
}
and then have your main view model different properties of this SubViewModel:
public class MyMainViewModel
{
public SubViewModel Sub1 { get; set; }
public SubViewModel Sub2 { get; set; }
public SubViewModel Sub3 { get; set; }
}
and then simply:
#Html.Partial("_BookField", Model.Sub1)
#Html.Partial("_BookField", Model.Sub2)
#Html.Partial("_BookField", Model.Sub3)
Of course it is the now the controller action responsibility to fill those view models (as always). And if you use editor/display templates your code might be even simpler, just like this:
#Html.DisplayFor(x => x.Sub1)
#Html.DisplayFor(x => x.Sub2)
#Html.DisplayFor(x => x.Sub3)
and because this strangely looks to me like a collection, well, you could use a collection:
public class MyMainViewModel
{
public SubViewModel[] Subs { get; set; }
}
and then simply:
#Html.DisplayFor(x => x.Subs)