ASP.NET MVC ViewData and DropDownList

[robertmacedonia]

Hello, I am just starting to play with ASP.NET MVC, I need to build a project for my school activities and I'm stuck with this (probably) simple thing, but I haven't got a clue...

I need to present a View that contains checkboxes to choose from, this part of the application allows an applicant for a job to enter his personal info, languages he speaks, education and work experience and skills. It's for IT crowd only.

So I handled the basic info, education and work experience using basic labels and textboxes, and now I wanna use checkboxes for choosing multiple languages that are spoken, and multiple skills.

Now, I am trying first to handle it by using DropDownLists, since I found an example like that in a tutorial, and then just modify it to use checkboxes.

Perhaps I should explain a little about the database design - the languages are stored in a "Language" table as simple as an ID and name, then the applicants are in the "Applicant" table and their relationship is stored in a M:N table "ApplicantSpeaksLanguage", containing the applicant's ID, the language's ID and a particular Weight's ID (another table).

Now, The appID is handled and not presented to be entered by the user, the weight ID - I';m just ignoring it for now, I am manually entering one valid value, and I wanna concentrate on the LanguageID column value - I will post the code here now. Now here's a part of the problem - I am presenting a DropDownList of language names to choose from, and when I post to the server I get a new record in the Language table, e.g. if English was entered and offered to the user at the start, and English is stored by the ID of 2, when a user selects English and posts, English is stored in the Languages table by another new ID, e.g. of 7, and then 7 is stored in the M:N table as the langID.. What I want is one of the existing langIDs to be entered in the M:N table, according to what language the user chose.

Maybe the problem is in the View...

I am using EntityFramework ORM and all of the tables are presented as classes - ApplicantSpeaksLang , Language etc...

I reckon this must be a beginner's mistake, but I just don't see it now.. And I haven't got a clue about working with checkboxes either...

Thanks for any help, regards

//GET: AddLanguages
        [Authorize]
        public ActionResult AddLanguages()
        {
            ApplicantSpeaksLang appLang = new ApplicantSpeaksLang();
            
           Language language = new Language();
            //Weight weight = new Weight();

            var allLanguages = repository.getAllLanguages();
            //var allWeights = repository.getAllWeights();

            ViewData["Languages"] = new SelectList(allLanguages, language.name);

            return View(appLang);
            
        }

        //POST: AddLanguages
      [HttpPost,Authorize]
        public ActionResult AddLanguages(FormCollection formValues)
        {
            ApplicantSpeaksLang appLang = new ApplicantSpeaksLang()
            {
                appID = repository.getApplicantByUsername(User.Identity.Name).applicantID
            };

            if (TryUpdateModel(appLang))
            {
                repository.AddAppSpeaksLang(appLang);
                repository.Save();

                return RedirectToAction("AddSkills");
            }

            Language language = new Language();

            var allLanguages = repository.getAllLanguages();

            ViewData["Languages"] = new SelectList(allLanguages, language.name);
            return View(appLang);


          
        }

Here's a part of the View:

<div class="editor-field">
                <%: Html.DropDownListFor(model => model.Language.name, ViewData["Languages"] as SelectList) %>
                <%: Html.ValidationMessageFor(model => model.langID) %>
            </div>

[robertmacedonia]

EDIT: I tried to change the DropDownListFor method by replacing the first parameter like this: Html.DropDownListFor(model => model.langID, ViewData["Languages"] as SelectList) and then (of course) I get an validation error - The value 'Deutsch' is not valid for langID. So, how do I present the name of the language to the user, and save its ID in the database... I would do this in Web Forms very easily, but here I am confused.

[robertmacedonia]

EDIT no2: I tried to change this:

ViewData["Languages"] = new SelectList(allLanguages, language.name, language.name, appLang.langID);

I used another overloading of the same method, this one takes these parameters: the collection, dataValueField, dataTextField, selectedValue.

And it does the same thing - adds a new language to the Languages table instead of inputting one of the already defined.

Also, what is the parameter: "string dataValueField"? The selected value is OK, this one is new to me