MVC Remote Attribute - Issue with submit - asp.net-mvc-3

Question

I'm trying to check if the combination of typeId & supplementId already exists in my database. So I've added a remoteattribute to my supplementId which does this. My problem is that the validation should trigger on changing either dropdownlist. I kinda fixed this clientside with the javascript on the ddl onchange. But now I'm not able to post my form. When I click the button, it focuses the last dropdownlist but doesn't show any errors and my Post method in the controller doesn't get fired. If I execute a form.submit() in chrome console the method gets called but validation is ignored. Anyone had this issue before?
BTW this code is cleaned to a minimum so labels, errormessages, etc could be missing,
these shouldn't be the issue.
Partial view:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<SupplementTypeClass>" %>
<script src="<%: Url.Content("~/Scripts/jquery-1.5.1.min.js") %>" type="text/javascript"></script>
<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>
<% using (Html.BeginForm("AddEditSupplementType", "Supplement"))
{ %>
<%: Html.ValidationSummary(true)%>
<fieldset>
<legend>
Add type
</legend>
<div class="editor-content">
<div class="editor-label">
<%: Html.LabelFor(model => model.SupplementId)%>
</div>
<div class="editor-field">
<%: Html.DropDownListFor(model => model.SupplementId, new SelectList(ViewBag.Supplements, "SupplementId", "Name", Model.SupplementId), "Select supplement", new { onchange = "$('#ddl').removeData('previousValue');$('#ddl').valid();" })%>
<%: Html.ValidationMessageFor(model => model.SupplementId)%>
</div>
</div>
<div class="editor-content">
<div class="editor-label">
<%: Html.LabelFor(model => model.TypeId)%>
</div>
<div class="editor-field">
<%: Html.DropDownListFor(model => model.TypeId, new SelectList(ViewBag.Types, "TypeId", "Name", Model.TypeId), "Select type", new { id ="ddl" })%>
<%: Html.ValidationMessageFor(model => model.TypeId)%>
</div>
</div>
<div class="editor-buttons">
<input type="submit" value="Save" />
</div>
</fieldset>
<% } %>
Controller:
[HttpPost]
public ActionResult AddEditSupplementType(SupplementTypeClass sup)
{
if (ModelState.IsValid)
{
//code to insert to DB
}
return RedirectToAction("FicheAddEditSupplementType", new { supplementTypeId = sup.supplementTypeId});
}
Class:
public class SupplementTypeClass
{
#region Members
public int SupplementId { get; set; }
[RemoteAttribute("SupplementTypeCheck", "Supplement", AdditionalFields = "SupplementId")]
public int TypeId { get; set; }
#endregion
}

Answer 1

The Remote attribute does Ajax calls using the GET method by default, not POST.
Make your you specificy the POST method in your model
[RemoteAttribute("SupplementTypeCheck", "Supplement", AdditionalFields = "SupplementId", HttpMethod="POST")]