Error: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection

Question

I use asp.net and EF 4 in C#.

I have a DetailsView with associated a ObjectDataSource.

<asp:ObjectDataSource ID="uxEntityDataSourceAuthors" runat="server" 
        SelectMethod="GetAuthors" 
        TypeName="WebProject.Web.Cms.AdminCms.Sections.CmsContents.ContentInformation">
    </asp:ObjectDataSource>

This the code for the Method:

    public IEnumerable<CmsAuthor> GetAuthors()
    {
    if (Roles.IsUserInRole("CMS-AUTHOR"))
    {
    using (CmsConnectionStringEntityDataModel context = new CmsConnectionStringEntityDataModel())
    {
                            // Display all Authors for specific logged-in User.
                            // Get Guid for current logged-in User.
                            MembershipUser myLoggedinUser = Membership.GetUser();
                            Guid myUserGuid = (Guid)myLoggedinUser.ProviderUserKey;
                            // Get list of Authors filtering my current logged-in User.
                            var myAuthorsForAuthor = from a in context.CmsAuthors
                                                     where a.UserId == myUserGuid
                                                     orderby a.LastName ascending
                                                     select a;
                            return myAuthorsForAuthor.AsEnumerable();
                        }
                    }
                    return null;  
 }

When I'm running the code I receive this error:

 The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.

Any idea what I'm doing wrong and how to fix it?

score 5 · Accepted Answer · answered Jun 28 '11 at 09:39

5

You're closing the CmsConnectionStringEntityDataModel called context before getting the data. Remember that AsEnumerable() will return a lazy enumerator, no data has been read from the source when you return and dispose of `context.

Use ToArray() (or ToList()) to ensure you get the data into memory before closing the source.

answered Jun 28 '11 at 09:39

Richard

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The list and array methods are called ToList() and ToArray() respectively – Ben Robinson Jun 28 '11 at 09:42
Hi, Id do not have AsArray() (or AsList()) only ToList(). – GibboK Jun 28 '11 at 09:47

Ben Robinson · Answer 2 · 2011-06-28T09:50:47.087

2

Calling AsEnumerable does not enumerate the collection it just changes it from IQeuryable<T> to IEnumerble<T>. You are disposing of the ObjectContext before the data is fetched from the database. Use ToList() which will enumerate the collection and fetch the data.

edited Jun 28 '11 at 09:50

answered Jun 28 '11 at 09:40

Ben Robinson

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Error: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection

2 Answers2