I get this error when I try to update: "The key-value pairs that define an EntityKey cannot be null or empty"

[Dylan]

I've been following the steps outlined here to practice CRUD operations with the Kendo UI Grid:

http://docs.kendoui.com/getting-started/using-kendo-with/aspnet-mvc/helpers/grid/batch-editing

And the incell editing is not actually saving the data changes I make. I've figured out that I'm running into ModelState errors, and so the ModelState.IsValid flag is false. Here is my edit method:

public ActionResult Editing_Update([DataSourceRequest] DataSourceRequest request, [Bind(Prefix = "models")]IEnumerable<TestTable> tests)
        {
            var results = new List<TestTable>();

            foreach (var modelStateValue in ViewData.ModelState.Values)
            {
                foreach (var error in modelStateValue.Errors)
                {
                    // Do something useful with these properties
                    var errorMessage = error.ErrorMessage;
                    var exception = error.Exception;
                }
            }

            if (tests != null && ModelState.IsValid)
            {
                using (var delta = new DeltaHREntities())
                {
                    foreach (var test in tests)
                    {
                        var entity = new TestTable
                        {
                            ID = test.ID,
                            Name = test.Name,
                            DateCreated = test.DateCreated
                        };

                        results.Add(entity);//store the test object for later use
                        delta.TestTables.Attach(entity);
                        //delta.Entry(test).State = EntityState.Modified;//why doesn't this work?
                        delta.ObjectStateManager.ChangeObjectState(entity, EntityState.Modified);
                    }
                    delta.SaveChanges();
                }
            }

            return Json(results.ToDataSourceResult(request, ModelState, test => new TestTable
            {
                Name = test.Name,
                DateCreated = test.DateCreated,
                ID = test.ID
            }));
        }

The exception that is raised is this:

"The key-value pairs that define an EntityKey cannot be null or empty"

Now the only part of my dataset that is null is the Name column, but this is set to Nullable in the edmx file, and the db field itself is set to nullable. So why do I keep getting this error message?

Another thing I'm confused about is how the demo (see the link above ) says to create a class called ProductViewModel in step 5. Why is this necessary when the Entity Framework has already created a Product table for you automatically? This seems to be an unneeded duplication of data. Thanks.

[Atanas Korchev]

Hello Dylan,

 The ProductViewModel is created to avoid the model state validation error caused by the EntityKey property binding. In general using view models is considered a good practice.

 If you don't want to create a view model you should clear the model state errors.

Regards,
Atanas Korchev
Telerik

[Freddie]

Hello Dylan,

We have a similar problem re ajax binding, did you get the solution?, if yes kindly share it to me because i did everything but until now I can't still find the right solution.

thanks

freddie

[Daniel]

Hello Freddie,

You could use one of the following approaches to avoid the modelstate error:

1. Create a ViewModel as Atanas already mentioned.
2. Project the data to an anonymous object with the same properties as demonstrated here.
3. Exclude the EntityKey from the binding:
   

   public ActionResult Update([Bind(Prefix="models",Exclude = "EntityKey")]IEnumerable<MyModel> data)

Regards,
Daniel
Telerik