Droplink value is always returning null in post action

Question

I am trying to build a form which contains state as droplink and given datasource as states .

here's the snippets of my employee model and state.

i am getting all the states in the get action of form and passing them.

public ActionResult EmployeeForm()
    {
        var sitecoreService = new SitecoreService("master");
        var statesFolder = sitecoreService.GetItem<States>("/sitecore/content/Global/States", x => x.LazyDisabled());
        ViewBag.States  = statesFolder.Children;   
        return View();
    }

when i am trying to retreive the values then the state is mapped correctly but in the post action of form it is null.

here's the snippet of my form's state

<div class="form-group">
    @Html.LabelFor(model => model.State, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.State, new SelectList(ViewBag.States,"Id","Name"), "select a state", new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.State, "", new { @class = "text-danger" })
    </div>
</div>

Post action code:

 public ActionResult CreateItem(EmployeeModel employeeModel)
    {
        ID id = new ID("{529829D4-9DE6-4E30-AF40-D67EA93D3271}");
        var sitecoreService = new SitecoreService("master");
        var parent = sitecoreService.GetItem<Employees>(id.Guid);
        employeeModel.Name = "employee-" + employeeModel.EmployeeId;
        sitecoreService.CreateItem(parent, employeeModel);
        return View("~/Views/ContactBook/Success.cshtml", employeeModel);                  
    }

Answer 1

Looking at your code, you're sending a state ID from your form in a POST action back to the server. Your model contains State property, but it's an object of State class. It's not possible to populate object from ID in a POST action automatically OOTB.

What you should do instead is to change the type of State property in EmployeeModel class to Guid or string (and maybe call it StateId) and then retrieve the item from database:

public class EmployeeModel : DepartmentModel
{
    public Guid StateId { get; set }
    // ... other properties
}