Partial view returns the Model with empty fields - asp.net-mvc-3

Question

In a web application using ASP.NET MVC 3, I pass from the controller a model with initialized properties as parameter to a partial view.
The view displays a dialog with a single textbox and on submit an action in the starting controller is fired (the action takes the same model type as parameter). The problem is that at this point only the property relative to the textbox field has a value, the one inserted by the user, while all the others are null, even if in the view they had a proper value.
How can I do in order to keep the properties from the view to controller once the submit button is clicked?
EDIT (added code):
//---------- This method in the controller call the Partial View and pass the model --------
[HttpPost]
public PartialViewResult GetAddCustomFormerClubDialog()
{
var order = GetCurrentOrder();
//Order has here all properties initialized
var dialogModel = new dialogModel<Order> { Entity = order, ControllerAddEntityActionName = "SelectOrder"};
return PartialView("Dialogs/AddOrder", dialogModel);
}
//----------------- Here the Partial View -----------------------------------
#model FifaTMS.TMS.Presentation.Model.Wizard.WizardDialogModel<Club>
<div>
#using (Ajax.BeginForm(Model.ControllerAddEntityActionName, "Orders", new AjaxOptions { HttpMethod = "POST"}))
{
#Html.LabelFor(a => a.Entity.Name)
#Html.TextBoxFor(a => a.Entity.Name, new { #class = "isrequired", style="width: 250px;" })
}
</div>
//-------- Here the method from the view (in the same controller as the first code portion) -----
[HttpPost]
public JsonResult SelectOrder(dialogModel<Order> OrderModel)
{
var order= OrderModel.Entity;
// But order has only the property Name set (in the view)
...
}

Answer 1

I was able to solve the issue simply by adding an hidden field for each needed property, like:
#Html.HiddenFor(p => p.Entity.OrderId, new { id = "OrderId" })
This is because from the PartialView a new instance of the Model is created and sent to the controller. Therefore only the properties set in the form are taken (in my case the only field was the OrderName related to the TextBox in the PartialView).