CheckBoxList does not update the model - asp.net-mvc-3

Question

I defined a Person entity:
public partial class Person
{
public string persID { get; set; }
public string last_name { get; set; }
public string driving_licence { get; set; }
}
where the driving licence is as follows:
public class DrivingLicence
{
public string drivingLicenceValue { get; set; }
public string drivingLicenceText { get; set; }
public DrivingLicence(string paValue, string paText)
{
drivingLicenceValue = paValue;
drivingLicenceText = paText;
}
}
having a repository where is defined this function:
public List<DrivingLicence> GetAll()
{
try
{
var drivingLicenceList = new List<DrivingLicence>();
DrivingLicence oneDrivingLicence = new DrivingLicence("A", "A");
drivingLicenceList.Add(oneDrivingLicence );
oneDrivingLicence = new DrivingLicence("B", "B");
drivingLicenceList.Add(oneDrivingLicence );
oneDrivingLicence = new DrivingLicence("C", "C");
drivingLicenceList.Add(oneDrivingLicence );
oneDrivingLicence = new DrivingLicence("D", "D");
drivingLicenceList.Add(oneDrivingLicence );
return drivingLicenceList;
}
catch (Exception)
{
throw new Exception("An error occured. Failed to Get the list.");
}
}
Now: I want the driving licences displayed as a CheckBoxList and on submit I want the person to get assigned the checked driving licence categories, e.g.: the "A" and "C" categories are selected, the resulting person.driving_licence must be "AC".
The problem is that this does not happen, the person is created but the driving_licence property is empty. I payed attention that the check boxes name be identical to that of the corresponding property (Person.driving_licence).
Is that an error in the present code? Or should I modify the Person entity?
Thank you for your advice.
Here is the view model:
public class PersonFormViewModel
{
// Properties
public Person person { get; set; }
public SelectList DrivingLicenceList { get; set; }
public string ActionToPerform { get; set; }
public PersonFormViewModel() { }
// Constructor
public PersonFormViewModel(Person pPerson, SelectList pDrivingLicenceList)
{
person= pPerson;
DrivingLicenceList = pDrivingLicenceList;
if (String.IsNullOrEmpty(person.persID))
{
ActionToPerform = "Create";
}
else
{
ActionToPerform = "Edit";
}
}
}
The controller:
//
// GET: /Person/Create
[Authorize]
public ActionResult Create()
{
Person person = new Person();
SelectList drvLicenceList = new SelectList(drvLicenceRepository.GetAll(), "drivingLicenceValue", "drivingLicenceText");
return View("Create", new PersonFormViewModel(person, drvLicenceList));
}
//
// POST: /Person/Create
[HttpPost, Authorize]
public ActionResult Create(PersonFormViewModel model)
{
Person person = model.person;
SelectList drvLicenceList = new SelectList(drvLicenceRepository.GetAll(), "drivingLicenceValue", "drivingLicenceText");
if (ModelState.IsValid)
{
try
{
db.Entry(person).State = EntityState.Added;
db.SaveChanges();
return RedirectToAction("Details");
}
catch (...)
{
...
}
}
return View("Create", new PersonFormViewModel(person, drvLicenceList));
}
And the view:
#model MyApp.ViewModels.PersonFormViewModel
#{
ViewBag.Title = "Create";
}
#using (Html.BeginForm())
{
#Html.ValidationSummary(false, "Errors occured.")
<fieldset>
<legend>Fill in your details</legend>
#Html.LabelFor(model => model.person.last_name)
#Html.TextBoxFor(model => model.person.last_name)
#Html.ValidationMessageFor(model => model.person.last_name, "*")
#Html.HiddenFor(model => model.person.persID)
#foreach (var ctg in (Model.DrivingLicenceList))
{
<input type="checkbox" name="driving_licence" value=ctg.value />#ctg.Text
}
<input type="submit" value="Sauvegarder" class="submit" />
</fieldset>
}

Answer 1

I would use a collection property in order to store the selected driving licence categories (multiple checkboxes can be selected => collection):
public partial class Person
{
public string persID { get; set; }
public string last_name { get; set; }
public string[] driving_licence { get; set; }
}
and then you will need to fix the name of the checkbox in order for it to bind correctly:
#foreach (var ctg in Model.DrivingLicenceList)
{
<input type="checkbox" name="person.driving_licence" value="#ctg.Value" />
#ctg.Text
}
and if you wanted to preserve the selected values you will need to set the checked property accordingly:
#foreach (var ctg in Model.DrivingLicenceList)
{
<input type="checkbox" name="person.driving_licence" value="#ctg.Value" #((Model.person.driving_licence ?? Enumerable.Empty<string>()).Contains(ctg.Value) ? "checked=\"checked\"" : "") />
#ctg.Text
}
This being said, we now have a working solution but it is far from anything I would content myself with and stop here. From now on we could start refactoring this mess in order to comply with C# naming conventions (things like property names start with capital letter, ...), introduce real view models (which do not reference domain models), custom HTML helpers that will generate this checkbox lists to avoid writing loops in the views and hardcoding checkboxes, ...