MVC unique HTML IDs with helpers - c#

New to MVC
The model is a list of:
public class person
{
[Display(Name = "ID")]
public object personID{ set; get; }
[Display(Name = "Last Name")]
public object personLastName { set; get; }
[Display(Name = "First Name")]
public object personFirstName{ set; get; }
}
On the view:
#model = List<person>
foreach(person member in Model)
{
Html.LabelFor(member.personLastName)
Html.EditorFor(member.personLastName)
etc.
Each Label will focus on the first editor, I'm assuming due to all the IDs being the same.
Passing the id as "fieldname + id" in each helper works, but is tedious, is there any easy way of creating ids or a more appropriate way of doing things?
Thanks.

Looks like you are trying to allow editing of a List of models. I highly suggest you read Phil Haacked - Model Binding To A List. This is a great resource to get started.

Related

Strange error: No parameterless constructor defined for this object

I know this has been asked many times but I can't solve my problem which is very funny.
My model is simple:
public class RegisterModel
{
[Display(Name = "First name")]
[Required]
public string FirstName { get; set; }
[Display(Name = "Last name")]
[Required]
public string LastName { get; set; }
[Display(Name = "Email address")]
[RegularExpression(#"^([a-zA-Z0-9_\-\.]+)#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$", ErrorMessage = "Enter valid e-mail")]
[Required(ErrorMessage = "E-mail is empty")]
public string EmailAddress { get; set; }
public System.Web.Mvc.SelectList Countries { get; set; }
}
Action:
[AllowAnonymous]
public virtual ActionResult Register(RegisterModel data)
{
if (!HttpContext.User.Identity.IsAuthenticated)
{
ModelState.Clear();
var countries =
this.ClientRepositoryBuilder
.CountryClientRepository
.GetAllCountries();
data.Countries = new SelectList(countries, "Id", "CountryName");
return
this.View(data);
}
else
{
return
this.RedirectToAction(MVC.Home.Index());
}
}
As soon as I add Countries into my model, stuff stops working and it doesn't invoke POST Action, give me an error with firebug(it's ajax post):
No parameterless constructor defined for this object
Default Model binding can't deal with that object when trying to convert from information coming in request to RegisterModel.
Options:
separate "incoming request model" from "view model" (as it looks like you always setting that property in controller).
create custom model binding - check more MSDN: The Features and Foibles of ASP.NET MVC Model Binding, or SO When to use IModelBinder versus DefaultModelBinder.
If you want something like accepting list as request parameter - Model Binding to a List MVC 4 may have an answer.
Ok I did a mistake with type, don't even know how I did this mistake.. So I updated model with proper type for Countries and stuff works now:
[Required]
public int Countries { get; set; }
It was a mistake due mine tiredness ;)

Dropdownlist asp.net

I have an application that allows user to create new items. As it stands now the user need to fill out Title, body and category.
The category is a textbox but I would like to convert it to a dropdownlist. This is all connected to a database and when the user submits it the data should be saved in the database. Everything works fine as it stands now, I am only having trouble implementing the dropdownlist.
My model:
public class NewsItem
{
public int ID { get; set; }
[Required(ErrorMessage = "Title is Required")]
public string Title { get; set; }
[Required(ErrorMessage = "Body is Required")]
public DateTime DateCreate { get; set; }
public string Category { get; set; }
}
What is the quickest/best way implementing this. Should I do it in the model or can I assign the values available in the view?
Thanks in advance!
First, some semantics. Since Entity Framework comes along with MVC, the assumption is that your POCOs are "models". (Unfortunately, Microsoft kind of piles on by putting scaffolded POCOs in a "Models" folder). However, these are not models in terms of the "Model" in Model-View-Controller; instead, they are merely "entities", which is a fancy way of saying "pretty much just a DTO EF can use to stuff data from the database into."
I point that out to say this: no, you shouldn't put your drop down list choices on your entity. But, you shouldn't rely on the view for this either. What you really want here is a view model. You create a class that has just the fields you need to edit and any additional business logic your view needs (such as the choices of categories), and then you map your entity to and from this view model. As an example:
public class NewsItemViewModel
{
[Required(ErrorMessage = "Title is Required")]
public string Title { get; set; }
[Required(ErrorMessage = "Body is Required")]
public DateTime DateCreate { get; set; }
public string Category { get; set; }
public IEnumerable<SelectListItem> CategoryChoices { get; set; }
}
Notice that while this class is mostly the same, it doesn't contain an Id property, because this is not something you'd want the user to edit. Also, it includes a CategoryChoices property to hold the items for your drop down list.
Then in your controller, you would do something like:
public ActionResult CreateNewsItem()
{
var model = new NewsItemViewModel();
model.CategoryChoices = db.Categories.Select(m => new SelectListItem { Value = m.Name, Text = m.Name });
return View(model);
}
Basically, you're just newing up the view model so you can feed it to the view. You fill in your category choices before actually returning it, though. I've assumed they're also entities, but you would use whatever method you needed to fetch them here, otherwise.
For your post action:
[HttpPost]
public ActionResult CreateNewsItem(NewsItemViewModel model)
{
if (ModelState.IsValid)
{
// map view model to entity
var newsItem = new NewsItem
{
Title = model.Title,
Category = model.Category,
// and so on
}
db.NewsItems.Add(newsItem);
db.SaveChanges();
return RedirectToAction("Index");
}
model.CategoryChoices = db.Categories.Select(m => new SelectListItem { Value = m.Name, Text = m.Name });
return View(model);
}
I'm just doing a manual mapping from the view model to a new news item, here, but for real world scenarios, you'd probably want to integrate a mapping library for this, such as AutoMapper. Also, take note that in the case where there's an error, you must refill the category choices before returning the view again. These will not be posted by your form, so the model that was passed in will not have them.
Finally, in your view:
#model Namespace.To.NewsItemViewModel
...
#Html.DropDownListFor(m => m.Category, Model.CategoryChoices)

Null values on model after sending model to controller

I'm using .net MVC.
I have some values in a form like:
#Html.TextBoxFor(model => model.Name, new { #class = "form-control" })
On the controller, I get the data like:
public ActionResult NovaPessoa(Person person)
{
The problem is that I just can get values that I have placed the #Html.TextBoxFor markup.
All the other complex information, like person.ContactInformation is lost after submiting and I can't use the SaveChanges in Entity Framework, because it will give me an invalid object after using the Atach method.
The question is: Do I need to use the #Html.TextBoxFor markup for all my model properties, even if I'm not using then to display anything, just to have them on Controller?
You are correct. What people (incorrectly) do normally, is use HiddenFor:
#Html.HiddenFor(model => model.ContactInformation)
What you should be doing, is cutting down your model into a view model with only the appropriate properties.
So, don't use this model:
public class PersonVM {
public int PersonId { get; set; }
public string FirstName { get; set; }
public string Surname { get; set; }
public string ContactInformation { get; set; }
}
..if all you're doing is updating the contact information. Instead, create a new class for your model:
public class PersonContactInfoEditVM {
public int PersonId { get; set; }
public string ContactInformation { get; set; }
}
That's all you need. This saves you from creating invalid objects when you don't add 30 HiddenFor elements to your page .. resulting in very broken data.
You might be thinking "ugggghhhh, all that manual mapping from PersonContactInfoEditVM to Person... I don't want to be writing that sort of code". No one does.. which is why the following libraries exist:
AutoMapper
ValueInjector

#Html.DropDownListFor fails in partial view but not in Full Page View

I am having an issue where my PartialView DropDownListFor gets the error:
The ViewData item that has the key PlanId is of type System.int32 but must be of type
IEnumerable<SelectListItem>
#Html.DropDownListFor(model => model.PlanId, (SelectList)ViewBar.PlanNameSelectList, new {#class = "short" })
This error does not pop up when I go to the page that originally held this code. What I have done is gutted the core part of the code which has worked previously with another partialView, as long as I took out the DropDownListFor elements in the code. I did not need them for that partialView, but now that I need them the problem has come full circle.
I would greatly appreciate any help that can be given to me to help solve this problem. Other resources like calls to the partial are below
#Html.Partial("location", new MAO.Models.ViewModels.CreateTemplateModel{})
This is the model
public class CreateTemplateModel {
[Required(ErrorMessage = "{0} is required.")]
[RegularExpression("^[0-9]+$", ErrorMessage="Template Id can only contain numbers")]
[Display(Name = "Template ID")]
public string TNumber { get; set; }
[Required(ErrorMessage = "{0} is required.")]
[RegularExpression("^.[0-9]{4}(-[0-9]{3})?$", ErrorMessage = "H# Must follow either #XXXX or #XXXX-XXX pattern")]
[Display(Name = "HNumber")]
public string HNumber { get; set; }
[RequiredIfOtherIsEmpty("NewPlanName", ErrorMessage = "Please enter a Plan Name")]
[Display(Name = "Select Existing Plan Name")]
public int PlanId { get; set; }
[MaxLength(500, ErrorMessage="{0} can't be longer than 500 characters")]
[Display(Name = "Enter New Plan Name")]
public string NewPlanName { get; set; }
[RequiredIfOtherIsEmpty("NewParentOrganization", ErrorMessage = "Please enter a Parent Organization")]
[Display(Name = "Select Existing Parent Organization")]
public string ParentOrganization { get; set; }
[MaxLength(500, ErrorMessage = "{0} can't be longer than 500 characters")]
[Display(Name = "Enter New Parent Organization")]
public string NewParentOrganization { get; set; }
[Required(ErrorMessage = "{0} is required.")]
public int TemplateTypeId { get; set; }
}
There is a controller that is pretty long so I am not going to post that. If there are parts of the controller that would be helpful I can post those parts as well as anything else that I might have forgotten to include
Based on your comments, I'm suspecting that you're never rebinding your drop down list when you are returning your partial view. Your controller action for the partial should be building your dropdown list in an identical manner to the controller action that renders the full view. Compare the two and make sure that they match.
UPDATE: Your partial view action should look something like the following:
public ActionResult Location()
{
ViewBag.PlanNameSelectList = new SelectList(plans.Distinct(), "Id", "Name", plans.FirstOrDefault(plan => plan.Name == selectedPlan));
attachSelectLists(ViewBag);
return PartialView("Location");
}
What you are currently doing with
#Html.Partial("location", new MAO.Models.ViewModels.CreateTemplateModel{})
Is rendering the partial view "location" using a NEW CreateTemplateModel object, not an existing one. Instead, a better way to do it is to duplicate your controller actions. Create a new one specifically for your partial view (this is a simpler use case for now).
public ActonResult TestPartialView()
Instead of using #Html.Partial which renders a partial, try calling your new controller action instead, which will build your drop down list for you.
#Html.RenderAction("TestPartialView").
This will call your new controller action and render the partial on the page, preserving the controller logic. If you use #Html.Partial, it simply renders the partial view passing in whatever object you give it which, in this case, is a new, empty CreateTemplateModel.

ASP.NET MVC Exclude Data Annotation Attribute in Html.ValidationMessageFor

I use the EF-CF, and have the following entities:
Countries, Companies
Companies has a property called CountryId with StringLength attribute and the min and max restrictions (min 3 chars, max 3 chars, country id is ISO-Alpha-3). When the user needs to create a Company, I show a html element with all available countries. This is perfect!
However, when the I execute the jquery validator to the form, this checks for 3 selected options and not the length selected option value.
I need the StringLengthAttribute in my Country Model, I cannot remove it.
I hope to "remove" or "hide" the StringLengthAttribute in the call:
#Html.ValidationMessageFor(model => model.CountryId)
Thanks!
I think I understand your question. A possible solution would be to use a ViewModel to pass to the view as oppose to using the Company entity directly. This would allow you to add or remove data annotations without changing the entity model. Then map the data from the new CompanyViewModel over to the Company entity model to be saved to the database.
For example, the Company entity might look something like this:
public class Company
{
public int Id { get; set; }
[StringLength(25)]
public string Name { get; set; }
public int EmployeeAmount { get; set; }
[StringLength(3, MinimumLength = 3)]
public string CountryId {get; set; }
}
Now in the MVC project a ViewModel can be constructed similar to the Company entity:
public class CompanyViewModel
{
public int Id { get; set; }
[StringLength(25, ErrorMessage="Company name needs to be 25 characters or less!")]
public string Name { get; set; }
public int EmployeeAmount { get; set; }
public string CountryId { get; set; }
}
Using a ViewModel means more view presentation orientated annotations can be added without overloading entities with unnecessary mark-up.
I hope this helps!
Ready!
I remove the rule for the html control.
$("##(Html.HtmlIdNameFor(model => model.CountryId))").rules("remove", "rangelength");
The "rangelength" is the jquery validation rule for the StringLengthAttribute.
Where "Html.HtmlIdNameFor" is a helper to get the "Id" generated by ASP.NET MVC.
Review How to get the HTML id generated by asp.net MVC EditorFor

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