The value "" is invalid - entity-framework

Question

Why does the Edit screen show the value I'm editing but when I try to save, the Edit HTTPPOST has a null object?
Getting a an error I've tracked down but don't see the cause of. I have a class used for a drop list, so it only has AdvisoryTypeID and AdvisoryType. But now I'm creating screens for users to see all in a grid (Index), add new (Create), and change existing ones (Edit). The index screen reads from the DB no problem. So does Edit. Create doesn't need to.
But both Edit and Create give the same error on HTTPPOST. The error is "The Value 'whatever I typed in' is invalid". Debugging the code turned up why: the "advisoryTypes" variable is null for reasons I don't understand:
CONTROLLER (for Edit post)
[Authorize]
[HttpPost]
public ActionResult Edit(AdvisoryTypes advisoryType)
{
try
{
if (ModelState.IsValid) //never get past this because it's null above
etc....
}
I have compared this to another screen that does Edit and Create fine and they're identical (except field names, for example). I'm stumped.
MODEL
public class AdvisoryTypes
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int AdvisoryTypeID { get; set; }
[Display(Name = "Type")]
[Required]
public string AdvisoryType { get; set; }
}
CONTROLLER (for Edit Get)
[Authorize]
public ActionResult Edit(int id = 0)
{
AdvisoryTypes advisoryType = db.AdvisoryType.Find(id);
if (advisoryType == null)
{
return HttpNotFound();
}
return View(advisoryType);
}
VIEW
model TheNewSolution.Models.AdvisoryTypes
#{
ViewBag.Title = "Edit Advisory Type";
}
<h2>Edit Advisory Type</h2>
#*<br />*#
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>Advisory</legend>
<table>
<tr>
<td>
#Html.HiddenFor(model => model.AdvisoryTypeID)
<div class="editor-label">
#Html.LabelFor(model => model.AdvisoryType)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.AdvisoryType)
#Html.ValidationMessageFor(model => model.AdvisoryType)
</div>
</td>
</tr>
</table>
<p>
<input type="submit" value="Save" />
</p>
</fieldset>
}
<div>
#Html.ActionLink("Back to List", "Index")
</div>
#section Scripts {
#Scripts.Render("~/bundles/jqueryval")
}
PART TWO
Now some odd background: this is the first model/controller/view I created since updating EF from 5 to 6 alpha3 (had to because I had POCO and edmx in same project and this solved that bug). I created the model manually. When I tried to create the Controller via the wizard, the wizard gave an error "Unable to retrieve metadata for ProjectName.Models.AdvisoryProviders'. Unable to cast obect of type 'System.Data.Entity.Core.Objects.ObjectContext' to type 'System.Data.Objects.ObjectContext'.".
The result was having to manually create the controller by copying/pasting another one and making changes, then creating my views the same way. I'm suspicious this is all related but maybe not. If this proves unrelated I'll remove this and post as another question.

Answer 1

the error from EF of "Unable to retrieve metadata for ProjectName.Models.AdvisoryProviders i have seen before, but this has only been because i was using MySQL, the only way i found around this kind of error and to make sure everything worked was to use http://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b-89f2-846072eff19d to create models from the database, and then use http://blog.stevensanderson.com/2011/01/13/scaffold-your-aspnet-mvc-3-project-with-the-mvcscaffolding-package/ to create the controllers, with view, rather than the buggy version of create view for EF.
I posted about these problems a while back with EF5 and its a real pain, MVCScaffolding seems to handle that pain alot better than the built in TT templates with MVC 4
hope this helps

Answer 2

I am not sure why this resolved, but here's what I did. I needed to create the screens mentioned above (index with grid, create, edit) for three different things (types, providers, categories) in my app. I did the first, type, resulting in the above issues.
I decided to create the same for "providers" by copying and pasting the controllers and views from "type" screens, then changing the model and field names as needed, expecting the screen to have the same bugs. But the screens all worked. I did it again for "categories", which also worked. Then I deleted my failing Create and Edit screens for "type", and recreated them from the "providers" screens. And they worked.
I have no explanation.