I have a simple form with a textbox (and a model editor I want to render in specific cases)
#using (Html.BeginForm("Import", "Flow"))
{
#Html.TextBoxFor(model => model.IsConfirmed)
#if (Model.IsConfirmed)
{
#Html.EditorFor(m => m.Preview)
}
}
The model used in this view is the following
public class ImportViewModel
{
public Boolean IsConfirmed { get; set; }
public PreviewViewModel Preview { get; set; }
public ImportViewModel()
{
this.IsConfirmed = false;
}
}
The form posts on the following controller
public class FlowController
{
[HttpPost]
public ActionResult Import(ImportViewModel model)
{
try
{
if (ModelState.IsValid)
{
if (model.IsConfirmed)
{
// do something else
}
else
{
model.Preview = Preview(model.strCA, model.SelectedAccount);
model.IsConfirmed = true;
return View(model);
}
}
}
catch (Exception ex)
{
throw new Exception("arf", ex);
}
return RedirectToAction("Index", "Home");
}
}
On first load, the textbox contains "false"
When posted, the property IsConfirmed of the model is set to "true" and this model is passed to the same view.
I expect the textbox to be "true" but it is still "false"... moreover the Preview property is correctly rendered, so it means Model.IsConfirmed is indeed true...
Am I missing something ?
Thanks
Make sure you remove the value from the ModelState if you intend to modify it:
ModelState.Remove("IsConfirmed");
model.IsConfirmed = true;
The reason you need to do that is because, by design, all Html helpers (such as TextBoxFor) will first look for a value in the ModelState when binding and only not found they will use the value on your model. And since there's a value with the same name in the ModelState (coming from the POST request), that's what's being used.
Related
I'm getting an error with TryUpdateModel when the field doesn't have a value and it's not nullable in the database. If I change the field in the database to nullable, it works. Anybody know a fix to get this to work with non nullable fields? I'm new to MVC, so I'm just playing with a tutorial to try to understand it....
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Add(FormCollection form)
{
var movieToAdd = new Movies();
if (Request != null && Request.Form != null && Request.Form.HasKeys() && ValueProvider == null)
{
ValueProvider = new FormCollection(Request.Form).ToValueProvider();
}
//Deserialize (Include white list!)
TryUpdateModel(movieToAdd, new string[] { "Title", "Director" }, form.ToValueProvider());
// Validate
if (string.IsNullOrEmpty(movieToAdd.Title))
ModelState.AddModelError("Title", "Title is required!");
if (string.IsNullOrEmpty(movieToAdd.Director))
ModelState.AddModelError("Director", "Director is required!");
// If valid, save movie to database
if (ModelState.IsValid)
{
_db.AddToMovies1(movieToAdd);
_db.SaveChanges();
return RedirectToAction("Index");
}
// Otherwise, reshow form
return View(movieToAdd);
}
There are a few things I would change.
Modify your method signature to accept the strongly typed model that your ActionResult is expecting. From there you can check if the Model is valid or not and continue with saving to the database
Use strongly typed models and data annotations for validating your model
EG:
Create a model which you would use for the form Get And Post actions:
public class YourModel
{
[Required]
public string Title {get; set;]
[Required]
public string Director {get; set;}
}
Your Post ActionResult then becomes:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Add(YourModel postedform)
{
// If valid, save movie to database
if (ModelState.IsValid)
{
_db.AddToMovies1(postedform);
_db.SaveChanges();
return RedirectToAction("Index");
}
// Otherwise, reshow form
return View(postedform);
}
I am trying to work out the best way of using a viewmodel in the case of creating a new object.
I have a very simple view model that contains a contact object and a select list of companies.
private ICompanyService _Service;
public SelectList ContactCompanyList { get; private set; }
public Contact contact { get; private set; }
public ContactCompanyViewModel(Contact _Contact)
{
_Service = new CompanyService();
contact = _Contact;
ContactCompanyList = GetCompanyList();
}
private SelectList GetCompanyList()
{
IEnumerable<Company> _CompanyList = _Service.GetAll();
return new SelectList(_CompanyList, "id", "name");
}
I then have contact controller that uses this viewmodel and enable me to select a related company for my contact.
[Authorize]
public ActionResult Create()
{
return View(new ContactCompanyViewModel(new Contact()));
}
My issue is with the create method on the controller.
[Authorize]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(Contact _Contact)
{
try
{
_Service.Save(_Contact);
return RedirectToAction("Index");
}
catch
{
return View();
}
}
The problem is that the view returns an empty contact object, but! the company id is populated, this is because the dropdown list explicitly declares its field name.
#Html.DropDownList("parent_company_id",Model.ContactCompanyList)
The standard html form fields pass the objects values back in the format of contact.forename when using the HTML.EditorFor helper...
#Html.EditorFor(model => model.contact.forename)
I can access them if I use a FormCollection as my create action method paremeter and then explicitly search for contact.value but I cannot use a Contact object as a parameter to keep my code nice and clean and not have to build a new contact object each time.
I tried passing the actual view model object back as a parameter but that simply blows up with a constructor error (Which is confusing seeing as the view is bound to the view model not the contact object).
Is there a way that I can define the name of the Html.EditFor field so that the value maps correctly back to the contact object when passed back to the create action method on my controller? Or Have I made some FUBAR mistake somewhere (that is the most likely explanation seeing as this is a learning exercise!).
Your view model seems wrong. View models should not reference any services. View models should not reference any domain models. View models should have parameterless constructors so that they could be used as POST action parameters.
So here's a more realistic view model for your scenario:
public class ContactCompanyViewModel
{
public string SelectedCompanyId { get; set; }
public IEnumerable<SelectListItem> CompanyList { get; set; }
... other properties that the view requires
}
and then you could have a GET action that will prepare and populate this view model:
public ActionResult Create()
{
var model = new ContactCompanyViewModel();
model.CompanyList = _Service.GetAll().ToList().Select(x => new SelectListItem
{
Value = x.id.ToString(),
Text = x.name
});
return View(model);
}
and a POST action:
[HttpPost]
public ActionResult Create(ContactCompanyViewModel model)
{
try
{
// TODO: to avoid this manual mapping you could use a mapper tool
// such as AutoMapper
var contact = new Contact
{
... map the contact domain model properties from the view model
};
_Service.Save(contact);
return RedirectToAction("Index");
}
catch
{
model.CompanyList = _Service.GetAll().ToList().Select(x => new SelectListItem
{
Value = x.id.ToString(),
Text = x.name
});
return View(model);
}
}
and now in your view you work with your view model:
#model ContactCompanyViewModel
#using (Html.BeginForm())
{
#Html.DropDownListFor(x => x.SelectedCompanyId, Model.CompanyList)
... other input fields for other properties
<button type="submit">Create</button>
}
I'm again struggling at validating inputs.
Let's say I edit a customer and the field "name" is required via
[Required(ErrorMessage = Constants.ErrorMsgNameMissing)]
public string NAME { get; set; }
inside the model.
The edit method does
[HttpPost]
edit(ViewModel vm)
{
// some code here
try
{
UpdateModel(vm);
// some code there
}
catch (Exception e)
{
return View(vm);
}
}
While doing UpdateModel(vm), an exception is thrown if the name is empty. Then my view shows the Html.ValidationSummary(). So far, so good.
Now, if I create a customer via
[HttpPost]
create(ViewModel vm)
{
if (ModelState.IsValid) { ... }
}
I don't have the method UpdateModel() since there's nothing to update. And ModelState.IsValid seems to return true every time. Even if the ViewModel is null. So I run into trouble then.
How do I validate this? And what do I return in case of errors?
Update: I think it was too late yesterday. In fact, it DOES work. But I was hoping for an exception and forgot the else { ... }...
Try this:
[HttpPost, ValidateInput(true)]
create(ViewModel vm)
{
if (ModelState.IsValid) { ... }
}
(couldn't think of a better title, sorry)
So I've got my layout page, on this page there is a searchbar + options. Choosing whatever, should take you through to the search page, with the results etc. Fairly standard. What I've done to get this working is to create a MasterModel class, with a SearchDataModel class member on it. This SearchDataModel contains the various parameters for the search (search term, what fields to search on etc).
I've then strongly typed my layout page to the MasterModel class, and using a Html.BeginForm... I've constructed the search form for it. However all the checkboxes relating to the fields aren't checked by default, even though the default value for all the fields is true (via a private getter/setter setup).
Yet when I submit the form to the SearchController, all the checkboxes are set to true. So I'm a bit confused as to why it knows they should be true, yet not set the checkboxes to be checked?
Putting breakpoints in key places seems to show that the model isn't insantiated on the get requests, only the post to the Search controller?
I may be going about this all wrong, so if so, pointers as to the right way always appreciated.
public class MasterModel {
public SearchDataModel SearchModel { get; set; }
}
public class SearchDataModel{
private bool _OnTags = true;
private bool _OnManufacturers = true;
private bool _OnCountries = true;
[Display(Name= "Tags")]
public bool OnTags {
get { return _OnTags; }
set { _OnTags = value; }
}
[Display(Name= "Manufacturers")]
public bool OnManufacturers {
get { return _OnManufacturers; }
set { _OnManufacturers = value; }
}
[Display(Name= "Countries")]
public bool OnCountries {
get { return _OnCountries; }
set { _OnCountries = value; }
}
[Required]
[Display(Name="Search Term:")]
public string SearchTerm { get; set; }
}
Then in the _layout page:
#Html.CheckBoxFor(m => m.SearchModel.OnTags, new { #class="ddlCheckbox", #id="inpCheckboxTag" })
#Html.LabelFor(m =>m.SearchModel.OnTags)
Make sure you return a MasterModel with initialized SearchModel from your views:
public ActionResult Index()
{
var model = new MasterModel
{
SearchModel = new SearchDataModel()
};
return View(model);
}
Another possibility to implement this functionality than strongly typing your master layout to a view model is yo use Html.Action as shown by Phil Haack in his blog post.
I am having the following code, However the errors causght not being displayed. What is wrong ?
public ActionResult DeleteRateGroup(int id)
{
try
{
RateGroup.Load(id).Delete();
RateGroupListModel list = new RateGroupListModel();
return GetIndexView(list);
}
catch (Exception e)
{
RateGroupListModel model = new RateGroupListModel();
if (e.InnerException != null)
{
if (e.InnerException.Message.Contains("REFERENCE constraint"))
ModelState.AddModelError("Error", "The user has related information and cannot be deleted.");
}
else
{
ModelState.AddModelError("Error", e.Message);
}
return RedirectToAction("RateGroup", model);
}
}
#model MvcUI.Models.RateGroupListModel
#{
View.Title = "RateGroup";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h2>Rate Group</h2>
#Html.ValidationSummary()
#using (Html.BeginForm())
private ActionResult GetIndexView(RateGroupListModel model)
{
return View("RateGroup", model);
}
public ActionResult RateGroup(RateGroupListModel model)
{
return GetIndexView(model);
}
It looks like you're setting the ModelState error, then redirecting to another action. I'm pretty sure the ModelState gets lost when you do that.
Typically, you'd just render the RateGroup view directly from the DeleteRateGroup action, without the redirect, passing in your model if needed, like this:
return View("RateGroup", model);
If you want the ModelState to come along to the second action with you, take a look at MvcContrib's ModelStateToTempDataAttribute. Here's the attribute's description, from the MvcContrib source code's comments:
When a RedirectToRouteResult is returned from an action, anything in the ViewData.ModelState dictionary will be copied into TempData. When a ViewResultBase is returned from an action, any ModelState entries that were previously copied to TempData will be copied back to the ModelState dictionary.