DbContext has been disposed (ASP.NET MVC)

Question

I have GeneralRepository

Here is code

public class GeneralRepository
{



    public IEnumerable<Site> GetSites()
    {
        using (TraxgoDB ctx = new TraxgoDB())
        {
            return ctx.Sites;
        }
    }

    public Customer GetCustomer(int customerID, bool main = false)
    {
        using (TraxgoDB ctx = new TraxgoDB())
        {
            var customer = ctx.Customers.First(c => c.ID == customerID);
            if (main) customer = (customer as SubUser)?.MainUser ?? customer;

            return customer;
        }
    }
    public Dictionary<int,int> GetCustomerIDDictionary()
    {
        using (TraxgoDB ctx = new TraxgoDB())
        {
            return ctx.Customers.ToDictionary(
                c => c.ID,
                c => (c as SubUser) != null ? (int) (c as SubUser).MainUserID : c.ID
            );
        }
    }


}

In Global.asax i have this code that using repo and method from repo

 private ConcurrentDictionary<string, SiteViewModel> InitializeSites()
    {
        var repository = new GeneralRepository();
        var siteDictionary = repository.GetSites().ToDictionary(
            s => s.HostName.ToLower(),
            s => SiteViewModel.CreateCustomTrackerwebSite(s.HostName, s)
        );

        return new ConcurrentDictionary<string, SiteViewModel>(siteDictionary);
    }

When I run website I have this error

The operation cannot be completed because the DbContext has been disposed.

In this row var siteDictionary = repository.GetSites().ToDictionary

How I can solve this error?

Hm. Seems yes. I make `return ctx.Sites.ToList();` and now it runs well@Marisa — Евгений Сухомлин, Oct 02 '17 at 11:22

Mihai Alexandru-Ionut · Answer 1 · 2017-10-02T11:33:26.270

2

IEnumerable class requires an active context in order to perform its operations.

Objects with the type as IQueryable<T> and IEnumerable<T> don't actually "execute" until they are iterated over or otherwise accessed, such as being composed into a List<T>.

Just use .ToList method.

 return ctx.Sites.ToList();

edited Oct 02 '17 at 11:33

answered Oct 02 '17 at 11:22

Mihai Alexandru-Ionut

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Yes. I understood it, but I can make .ToList in repo method too? – Евгений Сухомлин Oct 02 '17 at 11:24
Yes, you can, but keep it in current code. In future, you can need to use `GetSites` method filter by some fields and it's more effient to make these filters on `IQueryable` data. – Mihai Alexandru-Ionut Oct 02 '17 at 11:25
Hm. Paste you code in Global.asax file and still have this error. If I write .ToList in method,website runs well. – Евгений Сухомлин Oct 02 '17 at 11:27
@ЕвгенийСухомлин, yes copy in the repo. – Mihai Alexandru-Ionut Oct 02 '17 at 11:29
@ЕвгенийСухомлин, sorry, my mistake i think that you return an `IQeuryable` from repo but you returned `IEnumerable` – Mihai Alexandru-Ionut Oct 02 '17 at 11:30

score 2 · Accepted Answer · answered Oct 02 '17 at 11:34

The method GeneralRepository.GetSites() returns a IQueryable, and IQueryable doesn't return any result, it just define the query expressions, and any result won't be return untill you execute that query (by calling a linq method for example).

And you can see in your method GetSites() that the dbContext is disposed just after returning the IQueryable Object (Which is just a query definition)

public IEnumerable<Site> GetSites()
{
    using (TraxgoDB ctx = new TraxgoDB())
    {
        return ctx.Sites;
    }
}

So to solve your problem, just change your method like below:

public IEnumerable<Site> GetSites()
{
    using (TraxgoDB ctx = new TraxgoDB())
    {
        return ctx.Sites.ToList();
    }
}

Thank's for answer so much – Евгений Сухомлин Oct 02 '17 at 11:36 — Евгений Сухомлин, Oct 02 '17 at 11:36
@ЕвгенийСухомлин You're welcome – Otman IGHOULASSEN Oct 02 '17 at 13:52 — Otman IGHOULASSEN, Oct 02 '17 at 13:52

DbContext has been disposed (ASP.NET MVC)

2 Answers2