Question

I am developing an application with SQL CE and EF Poco 4.

The following code

Context

public class Context : DbContext
{
    public DbSet<BoletimSemanal> BoletinsSemanais { get; set; }

    public Context()
        : base("name=DefaultConnection")
    {
    }
}

Model

public class BoletimSemanal
{
    [Key]
    public int ID { get; set; }
    public string Name { get; set; }
    public DateTime DateCreated { get; set; }
    public DateTime DateModified { get; set; }
    public int Week { get; set; }
    public int Year { get; set; }
}

Controller

public ActionResult Index()
{
    IQueryable<BoletimSemanal> boletins;
    using (var db = new Context())
    {
        var calInfo = DateTimeFormatInfo.CurrentInfo;
        var week = calInfo.Calendar.GetWeekOfYear(DateTime.Now, calInfo.CalendarWeekRule, calInfo.FirstDayOfWeek);


        boletins = (from boletim in db.BoletinsSemanais
                    where boletim.Week == week
                            && boletim.Year == DateTime.Now.Year
                    select boletim);
    }

    return View(boletins.DefaultIfEmpty());
}

Web.config

<connectionStrings>
    <add name="DefaultConnection" connectionString="Data Source=|DataDirectory|Data.sdf;" providerName="System.Data.SqlServerCe.4.0" />
</connectionStrings>

View

@model IEnumerable<SextaIgreja.Web.Models.BoletimSemanal>
@{
    ViewBag.Title = "Downloads";
}
<div id="boletim-semanal" class="column last">
    <p class="title">Boletim Semanal
    @if (Request.IsAuthenticated)
    { 
        @Html.ActionLink("+", "Create", "Downloads", new { @class="add" })
    }
    </p>
    <div class="content border">
        <p>Content</p>
        <ul>
        @foreach (var item in Model)
        {
            <li>@item.Name</li>
        }
        </ul>
    </div>
</div>

the following error occurs in foreach:

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

Description: An unhandled exception
occurred during the execution of the
current web request. Please review the
stack trace for more information about
the error and where it originated in
the code.

Exception Details:
System.ObjectDisposedException: The
ObjectContext instance has been
disposed and can no longer be used for
operations that require a connection.

Source Error:

Answer 1

From your code, I see that you are using IQueryable. This means that when the view iterates that IQueryable, ObjectContext is already disposed, so you can’t access the database. Note that when you are using IQueryable data from db is fetched when you are iterating over it (throug foreach in your example).

    IList<BoletimSemanal> boletins;

    boletins = (from boletim in db.BoletinsSemanais
                where boletim.Week == week
                        && boletim.Year == DateTime.Now.Year
                select boletim).ToList();

Try this and it should work.