Mvc3 DropdownlistFor error - asp.net-mvc

Question

I have a mvc3 dropdownlist containing Organization list.I am able to fill that using the code below.But when I submit the form, I am getting Id instead of name and the corresponding Id is null.
Controller
ViewBag.DropDownList =organizationModelList.Select(x => new SelectListItem { Text = x.Name, Value = x.Id.ToString() });
return view();
Model
public class SubscriberModel
{
public OrgnizationList Organization { get; set; }
public RegisterModel RegisterModel { get; set; }
public SubscriberDetails SubscriberDetails { get; set; }
}
public class OrgnizationList
{
[Required]
public ObjectId Id { get; set; }
[Required]
[DataType(DataType.Text)]
[Display(Name = "Name")]
public string Name { get; set; }
}
View
#
model FleetTracker.WebUI.Models.SubscriberModel
#using (Html.BeginForm((string)ViewBag.FormAction, "Account")) {
<div>
#Html.DropDownListFor(m => m.Organization.Name, (IEnumerable<SelectListItem>)ViewBag.DropDownList, "---Select a value---")
</div>
}
When I change it tom => m.Organization.Id, then the modelstate will change to not valid.

Answer 1

Do you really need the name to be returned instead of the Id? If yes then instead of this:
ViewBag.DropDownList =organizationModelList.Select(x => new
SelectListItem { Text = x.Name, Value = x.Id.ToString() });
do this:
ViewBag.DropDownList =organizationModelList.Select(x => new SelectListItem { Text = x.Name, Value = x.Name });
Then remove the Required attribute for OrgnizationList.Id. If OrgnizationList is an entity, which I think it is, then you'll run yourself into trouble. I suggest you have a viewmodel that represents your input. So you don't have to deal with unnecessary required fields.
But what if the Name is not unique? Why can't you just accept the Id and save it in your data store? You are not modifying the name of OrgnizationList, I assume.
UPDATE:
If you really need both then tuck the Id on a hidden field:
Your controller method
ViewBag.DropDownList =organizationModelList.Select(x => new SelectListItem { Text = x.Name, Value = x.Id });
Your model
public class SubscriberModel
{
public int OrganizationId { get; set; }
// your other properties goeshere
}
Your view
<div>
#Html.HiddenFor(m=>m.OrganizationId)
#Html.DropDownListFor(m => m.Organization.Name, (IEnumerable<SelectListItem>)ViewBag.DropDownList, "---Select a value---")
</div>
and a bit of js needed...
$("Organization_Name").change(function(){
$("#OrganizationId").val($(this).val());
});

Answer 2

I did it using
$(document).ready(function () {
$("#DropDownList").change(function () {
$("#Organization_Id").val($(this).val());
$("#Organization_Name").val($("#DropDownList option:selected").text());
});
});
#Html.HiddenFor(m=>m.Organization.Id)
#Html.HiddenFor(m=>m.Organization.Name)
#Html.DropDownList("DropDownList", string.Empty)
controller
ViewBag.DropDownList = new SelectList(organizationModelList, "Id", "Name");