asp.net mvc 4 - View not binding correcty with the model -

i can figure out why it's not binding. have form listbox in partial view reload everytime click on checkbox fill listbox.

the code of modelview form :

                            <div class="row-fluid">                                 <div class="span3">                                      <label>fonction(s):</label>                                 </div>                                 <div class="span9" id="listefonction">                                                                             @html.partial("listerfonction", model)                                                                  </div>                             </div>                               <div class="row-fluid">                                 <div class="span5 offset3">                                     <div class="fonctions_container">                                             @foreach (extranetclient.models.classes.fonctioncontact fonction in viewbag.fonctions)                                             {                                                 string coche = "";                                                 if ((@model.listefonctions).any(c => c.idfonction == fonction.idfonction))                                                 {                                                     coche = "checked";                                                 }                                                  <input type="checkbox" @coche class="checkbox" value="@fonction.idfonction" />@fonction.libellefonction <br />                                             }                                     </div>                                  </div>                             </div> 

so can see, render partial view after "email" textbox. code :

@html.labelfor(contact => contact.selectedfonctionids, "listefonctions") @html.listboxfor(contact => contact.selectedfonctionids, new multiselectlist(model.listefonctions, "idfonction", "libellefonction"), new { disabled = "disabled") 

the model associated view looks that:

    private list<int> _selectedfonctionids;     public list<int> selectedfonctionids     {                 {             return _selectedfonctionids ?? new list<int>();         }         set         {             _selectedfonctionids = value;         }     }      public list<fonctioncontact> listefonctions = new list<fonctioncontact>();     public multiselectlist listefonctionsselectlist     {                 {             return new multiselectlist(                       listefonctions,                       "idfonction", // datavaluefield                       "libellefonction" // datatextfield             );         }     }      public contact() { }      public contact( list<fonctioncontact> listefonctions, list<int> selectedfonctionids)     {         this.listefonctions = listefonctions;         this.selectedfonctionids = selectedfonctionids;     }      public contact(int idcontact, string nom, string prenom, string email, string telephonefixe, string telephoneport) {         this.idcontact = idcontact;         this.nom = nom;         this.prenom = prenom;         this.email = email;         this.telephonefixe = telephonefixe;         this.telephoneport = telephoneport;        }      public contact(int idcontact, string nom, string prenom, list<int> selectedfonctionids, list<fonctioncontact> listefonctions, string email, string telephonefixe, string telephoneport)     {         this.idcontact = idcontact;         this.nom = nom;         this.prenom = prenom;         this.selectedfonctionids = selectedfonctionids;         this.listefonctions = listefonctions;         this.email = email;         this.telephonefixe = telephonefixe;         this.telephoneport = telephoneport;     } 

but listbox of partial view not binding model. other informations not these in listbox. has idea ?

why forcing listbox's id here:

@html.listboxfor(contact => contact.selectedfonctionids,     new multiselectlist(model.listefonctions, "idfonction", "libellefonction"),     new { disabled = "disabled", **id="idfonctions"** }) 

listboxfor helper supposed generate listbox's id you, , id should same attribute should bind with. shouldn't selectedfonctionids?

was binding working before started using partialview? because previous question, see had:

@html.listboxfor(contact => contact.selectedfonctionids, model.listefonctionsselectlist, new { disabled = "disabled" }) 

in view (i.e., didn't set id attribute).