Argument is always null when using RemoteAttribute - model-view-controller

Question

I am trying to make my first remote-validation in MVC, which I cannot get to work since the argument my validation action receives is always null.
public class Book
{
[Remote("IsValidDate", "Validation")]
public DateTime ReleaseDate { get; set; }
}
Then I have some other values I need outside the Book class, wherefore I also created a BookModel:
public class BookModel
{
public Book Book;
public string SomeOtherValueNotInterestingInThisExample;
public BookModel(Book book)
{
Book = book;
// other stuff
}
}
Then my editing page contains:
...
<script src="#Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="#Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
.... and later
<div class="editor-label">
#Html.LabelFor(model => model.Book.ReleaseDate)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Book.ReleaseDate)
#Html.ValidationMessageFor(model => model.Book.ReleaseDate)
</div>
My ValidationController looks like this:
public class ValidationController : Controller
{
public JsonResult IsValidDate(string strDate)
{
bool isValid = DateHelper.IsValid(strDate);
if (isValid)
{
return Json(true, JsonRequestBehavior.AllowGet);
}
else
{
return Json("(remote - not valid)", JsonRequestBehavior.AllowGet);
}
}
}
My problem is, that my strDate argument in IsValidDate(string strDate) is always null. Appart from that my validation works fine, and if I force it to fail, it also returns the correct errormessage to the correct field.
I cannot figure out why strDate is always null. Is it because it is in a BookModel and thereby called "Book.ReleaseDate"?

Answer 1

Okay, here is a hack that works for me in this case. First I must admit that I was not aware that the argument in IsValidDate must be named the same as the field I want to validate. I know that now.
Here is the changed code:
public class ValidationController : Controller
{
public JsonResult IsValidDate(string date)
{
if (date == null)
date = GetQueryStringValue("date");
bool isValid = DateHelper.IsValid(date);
if (isValid)
{
return Json(true, JsonRequestBehavior.AllowGet);
}
else
{
return Json(false, JsonRequestBehavior.AllowGet);
}
}
private string GetQueryStringValue(string key)
{
return (from qStr in Request.QueryString.AllKeys
where qStr.ToLower().EndsWith(key.ToLower())
select Request.QueryString.Get(qStr)).FirstOrDefault();
}
}
Note that I have made a separate GetQueryStringValue, so other validators can use the same method.
My Book class now looks like this (only the problematic fields are mentioned here):
public class Book
{
[Remote("IsValidDate", "Validation", ErrorMessage = "Release date is not valid")]
public DateTime ReleaseDate { get; set; }
[Remote("IsValidDate", "Validation", ErrorMessage = "Start date is not valid")]
public DateTime StartDate { get; set; }
}
Comment to the solution: Basically I start to check if the argument in IsValidDate is null or not. If it is null, I go through all QueryString keys to see if there is an argument which ends with the field name I want and then populate my argument with that value.
That led me to another solution (which ONLY works here, because I know that I do not have additional fields that ends with the same field name - or should I say - partly field name). By saying that I only want to look at the partly key name "date" (instead of "releasedate") I can have this validator check all my date-fields in the View. But as mentioned: it only works, because I do not want additional fields in my Remote validation. If I wanted to compare e.g. "StartDate" with "ReleaseDate" I would get problems :-)
I have also moved my ErrorMessage to my DataAnnotations, so I can have different errormessages on the fields.
It is not nice - but it works!