MVC5 problems with DropDownList and view model - asp.net-mvc

Question

So I have a simple database table in the form of ID, EmployeeID, date etc. Which creates a normal model:
public partial class WorkItem
{
public int ID { get; set; }
public int EmployeeID { get; set; }
public int LocationID { get; set; }
[DataType( DataType.Date )]
[Display( Name = "Start date" )]
public System.DateTime StartDate { get; set; }
My problem occurs when I need to augment the functionality of this model and so I create a view model to group work items on a weekly basis.
public class WeeklyWorkItemsViewModel
{
public WorkItem WorkItemMonday { get; set; }
public WorkItem WorkItemTuesday { get; set; }
All works perfectly well for the DateTime field in my view (which is bound to the view model):
<div class="form-group">
#Html.LabelFor( model => model.WorkItemMonday.StartDate, "Week start date", htmlAttributes: new { #class = "control-label col-md-2" } )
<div class="col-md-10">
#Html.EditorFor( model => model.WorkItemMonday.StartDate, new { htmlAttributes = new { #class = "form-control" } } )
#Html.ValidationMessageFor( model => model.WorkItemMonday.StartDate, "", new { #class = "text-danger" } )
</div>
</div>
The problem occurs trying to bind the dropdownlilst, it gets populated correctly but the changes are not seen in the controller.
<div class="form-group">
#Html.LabelFor( model => model.WorkItemMonday.EmployeeID, "EmployeeID", htmlAttributes: new { #class = "control-label col-md-2" } )
<div class="col-md-10">
#Html.Hidden( "selectedEmployee" )
#Html.DropDownList( "EmployeeID", null, htmlAttributes: new { #class = "form-control" } )
#Html.ValidationMessageFor( model => model.WorkItemMonday.EmployeeID, "", new { #class = "text-danger" } )
</div>
</div>
The StartDate is updated in the controller.
After mucho head scratching, I finally had to get around this using:
#Html.Hidden( "selectedEmployee" )
And updating this in JQuery. I did try using #html.DropDownListFor but no joy so far.
Can anyone see what's wrong before I pull ALL my hair out.

Answer 1

You model does not contain a property named EmployeeID. But it does have ones named WorkItemMonday.EmployeeID and WorkItemTuesday.EmployeeID.
Stop using DropDownList() and use the strongly typed DropDownListFor() method so that you correctly bind to your model properties.
Modify you view model to include a property for the SelectList
public IEnumerable<SelectListItem> EmployeeList { get; set; }
and populate it in the GET method before you pass the model to the view. Then in the view use
#Html.DropDownListFor(m => m.WorkItemMonday.EmployeeID, Model.EmployeeList, new { #class = "form-control" })
....
#Html.DropDownListFor(m => m.WorkItemTuesday.EmployeeID, Model.EmployeeList, new { #class = "form-control" })
which will correct generate the name="WorkItemMonday.EmployeeID" and name="WorkItemTuesday.EmployeeID" attributes so that they will bind to your model when you post.