I have an experience in work with ASP.NET forms, but new to MVC.
How can I get data from shared views on postback?
In ASP.NET Forms I can write something like this:
ASP.NET Forms:
Model code:
public class MyModelItem
{
// Just TextBox is enough for editing this
public string SimpleProperty { get; set; }
// For this property separate NestedItemEditor.ascx is required
public MyModelNestedItem ComplexProperty { get; set; }
}
public class MyModelNestedItem
{
public string FirstProperty { get; set; }
public string SecondProperty { get; set; }
}
Behavior:
Control for editing MyModelNestedItem is separate ASCX control NestedItemEditor.ascx
This is just for example, MyModelNestedItem can be much more complex, I just want to give idea what I mean.
Now when I showing this item for editing, I'm showing one asp:TextBox and one NestedItemEditor.ascx. On page postback I'm gathering data from both and that's it.
Problem with MVC:
When I'm trying to implement this scenario with MVC, I'm using customized EditorFor (through using UIHint and creating shared view). So this shared view Views\Shared\EditorTemplates\MyModelNestedItem.cshtml can now display data that is already in MyModelNestedItem property but I have no idea how to make it return new entered data.
When parent controller recieves a post request, data seems to be in Request.Form, but which is civilized way to reach it? Sure, the best solution will be if data will fetch automatically into the MyModelItem.ComplexProperty.
The action which is called on post needs to be something like:
[HttpPost]
public ActionResult Index(MyViewModel mdl)
Then all the properties of the model which have input controls (or hidden inputs) on the form will have the data which was entered on the form (or passed to it or modified by javascript, in the case of hidden inputs).
This assumes that MyViewModel is the model referenced in your view.
Writing an ActionResult method in the controller with the complex type simply worked for me:
public class Topic
{
public Topic()
{
}
public DetailsClass Details
{
get;
set;
}
}
public class DetailsClass
{
public string TopicDetails
{
get;
set;
}
}
The view:
#modelTopic
#using (Html.BeginForm("Submit","Default"))
{
#Html.EditorFor(m=>m.Details)
#:<input type="submit" />
}
The controller:
public ActionResult Index()
{
Topic topic = new Topic();
return View( topic);
}
public ActionResult Submit(Topic t)
{
return View(t);
}
When submited, the Topic t contains the value i ented within the editor (Assuming You have a custom editor for the complex type, DetailsClass in my sample)
Related
How to save two Entities from one View. Suppose I have two Entities Party and Person with One to Many relation. Now I need to save both Entities from Party View. I am using ASP.NET MVC4.
public partial class Cm_Opt_Pty_Party_S
{
public Cm_Opt_Pty_Party_S()
{
this.Cm_Opt_Psn_Person_S = new HashSet<Cm_Opt_Psn_Person_S>();
}
public int Pty_ID { get; set; }
public Nullable<int> Pty_PARTYTYPECODE { get; set; }
public string Pty_FULLNAME { get; set; }
public string Pty_GOVTID { get; set; }
public Nullable<int> Pty_GOVTIDTC { get; set; }
public Nullable<int> Pty_GOVTIDSTAT { get; set; }
public virtual ICollection<Cm_Opt_Psn_Person_S> Cm_Opt_Psn_Person_S { get; set; }
}
What you can do is create a ViewModel This class would contain the relevant properties needed to create both entities.
Then you base your View on the ViewModel instead, and pass that to the controller.
When you want to save the entities, you can build up the separate entities and save them.
I have a better understanding of your issue, so editing this answer to show the solution I would use.
Your Controller will deliver the Party object to your view for displaying the Party information. Using a loop you can display the items contained in the collection.
#foreach(var m in Model.Persons)
{
#Html.DisplayFor(model=>m.FirstName)
#Html.DisplayFor(model=>m.Surname)
}
When you want to add more items into the collection, you will need to render a partial view or new view containing a form for adding a Person. It will be strongly typed as Person model and the Controller action recieving the post will be expecting a Person
If for example a Person just had a FirstName,Surname and PartyId the form would use these helpers in your view
#Html.TextboxFor(m=>m.FirstName)
#Html.TextboxFor(m=>m.Surname)
#Html.TextBoxFor(m=>m.PartyId)
You then submit that back to your controller, and have logic for adding the person to the collection. Then return the view with Party model containing the newly added Person in the Persons collection.
Using #Ajax.BeginForm or some custom Jquery/Javascript you could handle this async to prevent page refreshing during the process.
If you don't want to do it this way, another option is EditorTemplates. See here for example: ASP.NET MVC LIST and Create in same view
Obviously there are a number of ways to do this, but I thought I'd ask for a little feedback on benefits and drawbacks of the approaches.
First of all, the NerdDinner tutorial's Edit Action is in the form (say Form A):
[HttpPost]
public ActionResult Edit(int id, FormCollection collection) {
It seems to me that if you shape your ViewModels well to match your views, that the approach Form B:
[HttpPost]
public ActionResult Edit(MyViewModel mvm) {
just seems like a better, cleaner approach. I then just map the VM properties to the Model properties and save. However, if this ViewModel has other entities embedded in it that are initialized via the constructor (for example in the nerddinner tutorial), then this edit action fails if there is no default constructor and you'd have to use the first approach.
So, the first question is do you agree that generally Form B is usually better? Are there drawbacks?
Secondly, it seems then if Form B is used, the decorator type validation would need to be in the ViewModel. Are there advantages of embedding entities in ViewModels and keeping the validation at the entity level only?
This is a pretty general SO question.
the first question is do you agree that generally Form B is usually better?
The only time I do not use Form B is when I upload files. Otherwise, I don't believe anyone should ever need to use Form A. The reason I think people use Form A is a lack of understanding of the abilities of ASP.Net's version of MVC.
Secondly, it seems then if Form B is used, the decorator type validation would need to be in the ViewModel.
Sort of / it Depends. I'll give you an example:
public IValidateUserName
{
[Required]
string UserName { get; set; }
}
public UserModel
{
string UserName { get; set; }
}
[MetadataType(typeof(IValidateUserName))]
public UserValiationModel : UserModel
{
}
The validation decorator is in an interface. I'm using the MetadataType on a derived class to validate the derived type. I personally like this practice because it allows reusable validation and the MetadataType/Validation is NOT part of the ASP.NET core functionality, so it can be used outside of ASP.Net (MVC) application.
Are there advantages of embedding entities in ViewModels ..
Yes, I do my absolute best to never pass a basic model to the view. This is an example of what I don't do:
public class person { public Color FavoriteColor { get; set; } }
ActionResult Details()
{
Person model = new Person();
return this.View(model);
}
What happens when you want to pass more data to your view (for partials or layout data)? That information is not Person relevant most of the time so adding it to the Person model makes no sense. Instead, my models typically look like:
public class DetailsPersonViewModel()
{
public Person Person { get; set; }
}
public ActionResult Details()
{
DetailsPersonViewModel model = new DetailsPersonViewModel();
model.Person = new Person();
return this.View(model);
}
Now I can add required data the DetailsPersonViewModel that view needs beyond what a Person knows. For example, lets say this is going to display a for with all the colors for the Person to pick a favorite. All the possible colors aren't part of a person and shouldn't be part of the person Model, so I'd add them to the DetailPersonViewModel.
public class DetailsPersonViewModel()
{
public Person Person { get; set; }
public IEnumerable<Color> Colors { get; set; }
}
.. and keeping the validation at the entity level only?
System.ComponentModel.DataAnnotations weren't designed to validate properties' properties, so doing something like:
public class DetailsPersonViewModel()
{
[Required(property="FavoriteColor")]
public Person Person { get; set; }
}
Doesn't exist and doesn't make sense. Why ViewModel shouldn't contain the validation for the entity that needs validation.
this edit action fails if there is no default constructor and you'd have to use the first approach.
Correct, but why would a ViewModel or a Entity in a ViewModel not have a parameterless constructor? Sounds like a bad design and even if there is some requirement for this, it's easily solved by ModelBinding. Here's an example:
// Lets say that this person class requires
// a Guid for a constructor for some reason
public class Person
{
public Person(Guid id){ }
public FirstName { get; set; }
}
public class PersonEditViewModel
{
public Person Person { get; set; }
}
public ActionResult Edit()
{
PersonEditViewModel model = new PersonEditViewModel();
model.Person = new Person(guidFromSomeWhere);
return this.View(PersonEditViewModel);
}
//View
#Html.EditFor(m => m.Person.FirstName)
//Generated Html
<input type="Text" name="Person.FirstName" />
Now we have a form that a user can enter a new first name. How do we get back the values in this constructor? Simple, the ModelBinder does NOT care what model it is binding to, it just binds HTTP values to matching class properties.
[MetadataType(typeof(IPersonValidation))]
public class UpdatePerson
{
public FirstName { get; set; }
}
public class PersonUpdateViewModel
{
public UpdatePerson Person { get; set; }
}
[HttpPost]
public ActionResult Edit(PersonUpdateViewModel model)
{
// the model contains a .Person with a .FirstName of the input Text box
// the ModelBinder is simply populating the parameter with the values
// pass via Query, Forms, etc
// Validate Model
// AutoMap it or or whatever
// return a view
}
I have not yet taken a look at the NerDinner project, however, I generally try to avoid having a ViewModel in the POST of an action and instead, only have the elements of the "form" submitted.
For instance, if the ViewModel has a Dictionary that is used in some kind of dropdown, the entire dropdown will not be submitted, only the selected value.
My general approach is:
[HttpGet]
public ActionResult Edit(int id)
{
var form = _service.GetForm(id);
var pageViewModel = BuildViewModel(form);
return View(pageViewModel);
}
[HttpPost]
public ActionResult Edit(int id, MyCustomForm form)
{
var isSuccess = _service.ProcessForm(id);
if(isSuccess){
//redirect
}
//There was an error. Show the form again, but preserve the input values
var pageViewModel = BuildViewModel(form);
return View(pageViewModel);
}
private MyViewModel BuildViewModel(MyCustomForm form)
{
var viewModel = new MyViewModel();
viewModel.Form = form;
viewModel.StateList = _service.GetStateList();
return viewModel;
}
I'm working with ASP.NET MVC 4, but I on't think that matters for the purpose of this question.
I have a relatively complex model for my edit view. Like this:
public class Recipe_model
{
public string Name { get; set; }
public List<Recipe_Ingredient_model> Ingredients { get; set; }
}
where Ingredients is
public class Recipe_Ingredient_model
{
public int RecipeID { get; set; }
public int? UnitID { get; set; }
public double? Quantity { get; set; }
public Ingredient_model Ingredient { get; set; }
}
which itself contains the Ingredient model.
When I make a form for this, the built-in Html.EditorFor() doesn't work for anything past the properties of the Recipe_model, so I'm using partial views to display the editor for each of the sub-models.
That works fine as far the interface goes, but when I submit the form to the controller and try to bind to the Recipe_model automatically using
[HttpPost]
public ActionResult Edit(Recipe_model model)
{
return View(model);
}
it fails because the ids of the input elements in the partial views do not conform to the correct pattern (I think ParentModel_Property).
Short from hard-coding the ids in the partial view or binding manually from the FormCollection in the controller, is there some way to get the correct ids generated in the partial view so that the model will bind automatically on submit?
This is common problem. Instead of simple partials, use EditorTemplates (special folder for models) and binding will work automatically.
For example look at this question: Updating multiple items within same view
in addition to the answer given by #WebDeveloper
you can also try and create a custom model binder though a little more complex but will add to the ease of posting and binding form value to the objects in long run
have a look here http://patrickdesjardins.com/blog/asp-net-mvc-model-binding
you will have to manually take all the form values and bind them to the model once and then you will be able to use the #HtmlFrom methods on the razor to do anything and you will get all the value inside the objects inside the action methods as you like.
There are a lot of articles devoted to working with data in MVC, and nothing about MVC 2.
So my question is: what is the proper way to handle POST-query and validate it.
Assume we have 2 actions. Both of them operates over the same entity, but each action has its own separated set of object properties that should be bound in automatic manner. For example:
Action "A" should bind only "Name" property of object, taken from POST-request
Action "B" should bind only "Date" property of object, taken from POST-request
As far as I understand - we cannot use Bind attribute in this case.
So - what are the best practices in MVC2 to handle POST-data and probably validate it?
UPD:
After Actions performed - additional logic will be applied to the objects so they become valid and ready to store in persistent layer. For action "A" - it will be setting up Date to current date.
I personally don't like using domain model classes as my view model. I find it causes problems with validation, formatting, and generally feels wrong. In fact, I'd not actually use a DateTime property on my view model at all (I'd format it as a string in my controller).
I would use two seperate view models, each with validation attributes, exposed as properties of your primary view model:
NOTE: I've left how to combining posted view-models with the main view model as an exercise for you, since there's several ways of approaching it
public class ActionAViewModel
{
[Required(ErrorMessage="Please enter your name")]
public string Name { get; set; }
}
public class ActionBViewModel
{
[Required(ErrorMessage="Please enter your date")]
// You could use a regex or custom attribute to do date validation,
// allowing you to have a custom error message for badly formatted
// dates
public string Date { get; set; }
}
public class PageViewModel
{
public ActionAViewModel ActionA { get; set; }
public ActionBViewModel ActionB { get; set; }
}
public class PageController
{
public ActionResult Index()
{
var viewModel = new PageViewModel
{
ActionA = new ActionAViewModel { Name = "Test" }
ActionB = new ActionBViewModel { Date = DateTime.Today.ToString(); }
};
return View(viewModel);
}
// The [Bind] prefix is there for when you use
// <%= Html.TextBoxFor(x => x.ActionA.Name) %>
public ActionResult ActionA(
[Bind(Prefix="ActionA")] ActionAViewModel viewModel)
{
if (ModelState.IsValid)
{
// Load model, update the Name, and commit the change
}
else
{
// Display Index with viewModel
// and default ActionBViewModel
}
}
public ActionResult ActionB(
[Bind(Prefix="ActionB")] ActionBViewModel viewModel)
{
if (ModelState.IsValid)
{
// Load model, update the Date, and commit the change
}
else
{
// Display Index with viewModel
// and default ActionAViewModel
}
}
}
One possible way to handle POST data and add validation, is with a custom model binder.
Here is a small sample of what i used recently to add custom validation to POST-form data :
public class Customer
{
public string Name { get; set; }
public DateTime Date { get; set; }
}
public class PageController : Controller
{
[HttpPost]
public ActionResult ActionA(Customer customer)
{
if(ModelState.IsValid) {
//do something with the customer
}
}
[HttpPost]
public ActionResult ActionB(Customer customer)
{
if(ModelState.IsValid) {
//do something with the customer
}
}
}
A CustomerModelBinder will be something like that:
public class CustomerModelBinder : DefaultModelBinder
{
protected override void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, System.ComponentModel.PropertyDescriptor propertyDescriptor)
{
if (propertyDescriptor.Name == "Name") //or date or whatever else you want
{
//Access your Name property with valueprovider and do some magic before you bind it to the model.
//To add validation errors do (simple stuff)
if(string.IsNullOrEmpty(bindingContext.ValueProvider.GetValue("Name").AttemptedValue))
bindingContext.ModelState.AddModelError("Name", "Please enter a valid name");
//Any complex validation
}
else
{
//call the usual binder otherwise. I noticed that in this way you can use DataAnnotations as well.
base.BindProperty(controllerContext, bindingContext, propertyDescriptor);
}
}
and in the global.asax put
ModelBinders.Binders.Add(typeof(Customer), new CustomerModelBinder());
If you want not to bind Name property (just Date) when you call ActionB, then just make one more custom Model Binder and in the "if" statement, put to return the null, or the already existing value, or whatever you want. Then in the controller put:
[HttpPost]
public ActionResult([ModelBinder(typeof(CustomerAModelBinder))] Customer customer)
[HttpPost]
public ActionResult([ModelBinder(typeof(CustomerBModelBinder))] Customer customer)
Where customerAmodelbinder will bind only name and customerBmodelbinder will bind only date.
This is the easiest way i have found, to validate model binding, and i have achieved some very cool results with complex view models. I bet there is something out there that i have missed, and maybe a more expert can answer.
Hope i got your question right...:)
I am new to MVC. I am developing an web application in asp.net MVC. I have a form through which users can get registered, after registration user redirected to ProfileView.aspx page. till here everything is fine.
Now I want to show the articles headings posted by that user right under his profile.
Right now I m using following code:
public ActionResult ProfileView(int id)
{
Profile profile = profileRepository.GetProfileByID(id);
var articles = articlesRepository.FindArticlesByUserID(id).ToList();
return View("ProfileView", profile);
}
Thanks for helping in advance
Baljit Grewal
I can think of two options:
Use the ViewData dictionary to store the articles.
public ActionResult ProfileView(int id)
{
Profile profile = profileRepository.GetProfileByID(id);
var articles = articlesRepository.FindArticlesByUserID(id).ToList();
ViewData["Articles"] = articles;
return View("ProfileView", profile);
}
Or, if you want to avoid using ViewData, create a ViewModel. A ViewModel is kind of a data transport object. You could create a ProfileViewModel class like this:
public class ProfileViewModel
{
public Profile Profile{ get; set; }
public IList<Article> Articles { get; set; }
}
or just include the Profile properties you are using in your view, this will make binding easier but you'll have to copy values from your Model to your ViewModel in your controller.:
public class ProfileViewModel
{
public int Id{ get; set; }
public string Name { get; set; }
.......
public IList<Article> Articles { get; set; }
}
If you go for this last option take a look at AutoMapper (an object to object mapper).
you will want your page to inherit from ViewPage and then you can use your model inside the .aspx markup like