Values don't change after posting back to view? - asp.net-mvc-3

Question

Edit: I've changed my question and code to clarify my question better
I've got this (strongly typed view) that does use the values provided in the controller for that specific model
I want to add something to a Model from another model, after posting back from my httpPost action nothing happens...
Thanks in advance!
--------------------------------------other code to clarify my question a bit more----
public class Address
{
public int Id { get; set;}
public String Name { get; set;}
}
public class OtherAddress
{
public int Id { get; set;}
public String Name { get; set;}
public String City { get; set;}
}
public class MasterModel
{
public Address Address { get; set;}
public List<OtherAddress> OtherAddressess { get; set;}
}
public ActionResult Create()
{
MasterModel Model = new MasterModel();
Model.Person = new Person();
Model.Address = new Address();
Model.OtherAdressess = new List<OtherAddress>();
DBContext _db = new DBContext();
Model.OtherAdressess = _db.OtherAddressess.Where(a=> a.City == "Amsterdam");
return View(Model);
}
in the view
#model Project.Models.MasterModel
List<SelectListItems> items = new List<SelectListItems>();
foreach(var a in Model.OtherAddressess)
{
SelectListItem item = new SelectListItem();
item.Value = a.Id.toString();
item.Text = a.Street;
}
#using (#Html.BeginForm())
{
<div>
<select name="otheraddress">
foreach(var i in Items)
{
<option value=#i.Value>#i.Text</option>
}
</select>
<input type="submit" name="select" value="Select Address"/>
</div>
<div>
#Html.EditorFor(model => Model.Address.Name)
<div>
<p>
<input type="submit" value="Submit"/>
</p>
}
in post
[HttpPost]
public ActionResult Create(MasterModel Model)
{
String otherAddressSelected = Request.Params["select"];
if(!String.IsNullOrEmpty(otherAddressSelected))
{
int id = int.Parse(Request.Params["otheraddress"]);
DBContext _db = new DBContext();
OtherAddress oa = _db.OtherAddress.Single(oa=> oa.Id == id);
Model.Address.Name = oa.Name;
return View(Model);
}
//other stuff here
}

Answer 1

If you want to change the value of your model in a [HttpPost] controller you have to remove the modelstate for the instance/attribute that you want to change. For example:
[HttpPost]
public ActionResult Index(SomeModel model)
{
ModelState.Remove("Name");
model.Name = "some new name";
return View(model);
}
Got the answer from this example

Answer 2

I would create action method called details that would accept person id as parameter:
public ActionResult Details(int id)
{
// Get person and display
}
Your Create action method is for creating Person type objects, and not displaying their details. So logically what you are doing doesn't seem right to me.
There should be action method to display view for creating a person and equivalent HTTP action method for persisting it into the database.
I would then re-direct to an action method for displaying Person type object information.
return RedirectToAction("Details", new { id = Person.Id });

Answer 3

The input helpers in asp.net mvc will use the post values if they can find any before looking at the model.
In this situation here I think the problem is that you are trying to do more then one thing in the Create POST action. A action (as with any method in the application) should only do one thing. In your case I would do something like this (if I understand the work flow correctly that is):
//Action: SelectAddress
public ActionResult SelectAddress() {
var addresses = _db.OtherAddressess.Where(a=> a.City == "Amsterdam");
return View(new SelectAddressViewModel(addresses));
}
//View SelectAddress
....
<ul>
#foreach(var address in Model.Addresses) {
<li>
<a href="#Url.Action("Create", "Product", new { addressId = address.Id })">
#Model.Name
</a>
</li>
}
</ul>
....
//Action Create
public ActionResult Create(int addressId) {
var address = _db.OtherAddress.Single(oa=> oa.Id == addressId);
var Model = new MasterModel();
Model.Person = new Person();
Model.Address = new Address {
Name = address.Name
}
return View(Model);
}