MVC drop down list - null error - model-view-controller

Question

I have generated Models classes using Entity Framework.
This is what I got:
public partial class Employees
{
public Employees()
{
this.Employees1 = new HashSet<Employees>();
this.Vacations = new HashSet<Vacations>();
}
public int EmployeeID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string MiddleName { get; set; }
public string Phone { get; set; }
public string JobTitle { get; set; }
public int ManagerID { get; set; }
public string LastUpdatedBy { get; set; }
public Nullable<System.DateTime> LastUpdatedDate { get; set; }
public bool Status { get; set; }
public virtual ICollection<Employees> Employees1 { get; set; }
public virtual Employees Manager { get; set; }
public virtual ICollection<Vacations> Vacations { get; set; }
}
Then I've created View Model for that class:
public class EmployeeViewModel
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string MiddleName { get; set; }
public string Phone { get; set; }
public string JobTitle { get; set; }
public int ManagerID { get; set; }
public string ManagerFullName
{
get
{
return FirstName + " " + LastName;
}
}
public bool Status { get; set; }
public virtual ICollection<Employees> Employees1 { get; set; }
public virtual Employees Manager { get; set; }
}
In EmplyeeControler class I have action:
public ActionResult Create()
{
EmployeeViewModel employeeVM = new EmployeeViewModel();
ViewBag.Employees1 = new SelectList(employeeVM.Employees1, "EmployeeID", "ManagerFullName");
return View(employeeVM);
}
And view:
<div class="editor-label">
#Html.LabelFor(model => model.ManagerID, "Manager")
</div>
<div class="editor-field">
#Html.DropDownList("ManagerID", "--- Select Manager ---")
#Html.ValidationMessageFor(model => model.ManagerFullName)
</div>
But I am receiving error on line:
Value cannot be null. Parameter name: items
ViewBag.Employees1 = new SelectList(employeeVM.Employees1, "EmployeeID", "ManagerFullName");
What is wrong in my code?

Answer 1

<div class="editor-label">
#Html.LabelFor(model => model.ManagerID, "Manager")
</div>
<div class="editor-field">
#Html.DropDownListFor(x => x.ManagerID, (IEnumerable<SelectListItem>)ViewBag.Employees1,"--- Select Manager ---"));
#Html.ValidationMessageFor(model => model.ManagerFullName)
</div>
More Details See this link