Linq Order By not working

Question

The Linq query "order by" is not working and I've followed all the suggestions found on your site and other sites. Any assistance would be appreciated.

    [WebGet]
    public IQueryable<vw_providercharge_providers> GetChargeProviders(int submitted)
    {
        var results = (from p in this.CurrentDataSource.vw_providercharge_providers
                       where p.submitted == submitted
                       orderby p.fullname
                       select p);
        return results;
    }

---

Thanks for your input!

Yes, this is a WebGet method for a WCF data service. I get a 400 error if I don't return an IQueryable type, so I modified your suggestion a little. Unfortunately, it still seems to disregard any order-by.

[WebGet]
public IQueryable<vw_providercharge_providers> GetChargeProviders(int submitted)
{
    var results = (from p in this.CurrentDataSource.vw_providercharge_providers
                   where p.submitted == submitted
                   orderby p.fullname
                   select p).ToArray();
    results.OrderBy(p => p.patientname);
    return results;
}

Answer 1

I notice you return an IQueryable<T> - are you calling any LINQ methods on the result before you enumerate it?

Not all LINQ methods preserve order. Most commonly, calling Distinct() after you do the ordering will destroy the order.

Answer 2

Since your method is a marked with a WebGet attribute, I'm assuming that you are calling this method from a Web endpoint, therefore you may need to collapse the collection prior to send it through internet.

Try:

[WebGet]
public vw_providercharge_providers[] GetChargeProviders(int submitted)
{
    var results = (from p in this.CurrentDataSource.vw_providercharge_providers
                   where p.submitted == submitted
                   orderby p.fullname
                   select p).ToArray();
    return results;
}

This way you have the guarantee that the GetChargeProviders method returns and array instead of an linq expression.

Regards,

Answer 3

I found the cause of the issue.

I had not set the "fullname" column as an Entity Key for the "vw_providercharge_providers" data model entity. Only the identity column was set as an Entity Key. I didn't realize that was a requirement to use it in an order by clause.

Thanks again for your input.