Asp.Net MVC dropdownlist not posting value to controller -> database - asp.net-mvc

Question

my development environment is ASP.NET MVC 5 using Entity Framework 6 using a code-first workflow.
My problem: When trying to add a new record to the database, the values from my two dropdownlists are not being included. All the other fields are indeed saving to the database.
I am passing a ViewModel to the view in question:
public class NewItemViewModel
{
public IEnumerable<Category> Categories { get; set; }
public Item Item { get; set; }
public IEnumerable<Donor> Donors { get; set; }
}
The domain models I am using:
public class Item
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int Quantity { get; set; }
public bool IsActive { get; set; }
public Category Category { get; set; }
public Donor Donor { get; set; }
}
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Donor
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName { get { return FirstName + " " + LastName; } }
public string Email { get; set; }
}
The relevant controller: This New() action is simply used to pass data to the view for the form to be submitted
public ActionResult New()
{
var itemCategories = _context.ItemCategory.ToList();
var donors = _context.Donors.ToList();
var viewModel = new NewItemViewModel
{
Categories = itemCategories,
Donors = donors
};
return View(viewModel);
}
Here is my actual action that adds the submitted data to the database:
// Create a new item.
[HttpPost]
public ActionResult Create(Item item)
{
_context.Items.Add(item);
_context.SaveChanges();
return RedirectToAction("Index", "Item");
}
And lastly, the view itself (I will minimize the code here):
#using (Html.BeginForm("Create", "Item"))
{
<div class="form-group">
#Html.LabelFor(m => m.Item.Donor)
#Html.DropDownListFor(m => m.Item.Donor, new SelectList(Model.Donors, "Id", "FullName"), "Who donated this item?", new { #class = "form-control" })
</div>
<div class="form-group">
#Html.LabelFor(m => m.Item.Category)
#Html.DropDownListFor(m => m.Item.Category, new SelectList(Model.Categories, "Id", "Name"), "Select Item Category", new { #class = "form-control" })
</div>
}
To reiterate the problem I am having: The values of the dropdownlist for Category and Donor are not saving to the database, whereas the others (non-navigation properties?) Name, Description, Quantity, etc. is working correctly.
Am I using the ViewModel the right way? I was under the impression that the MVC framework knows how to deal with passing the Item object parameter in the Create() action - mapping what it needs to within the Item entity.
Any help would be much appreciated. Thank you.

Answer 1

In the NewItemViewModel you have not created property to hold the selected values from dropdown
public class NewItemViewModel
{
public IEnumerable<Category> Categories { get; set; }
public int SelectedCategory{get;set;}
public Item Item { get; set; }
public int SelectedDonor{get;set;}
public IEnumerable<Donor> Donors { get; set; }
}
#using (Html.BeginForm("Create", "Item"))
{
<div class="form-group">
#Html.LabelFor(m => m.Item.Donor)
#Html.DropDownListFor(m => m.SelectedDonor, new SelectList(Model.Donors, "Id", "FullName"), "Who donated this item?", new { #class = "form-control" })
</div>
<div class="form-group">
#Html.LabelFor(m => m.Item.Category)
#Html.DropDownListFor(m => m.SelectedCategory, new SelectList(Model.Categories, "Id", "Name"), "Select Item Category", new { #class = "form-control" })
</div>
}