在MVC中使用动作result、ObjectContext来呈现部分视图

Question

我试图在我的视图中使用以下代码填充部分视图:

@{Html.RenderAction("AppointmentsView", "Appointment", new { id = Model.PatientId });}

我的动作结果如下:

    public ActionResult AppointmentsView(int id)
    {
        using (var context = new WaysToWellnessDB())
        {
            IEnumerable<AppointmentDiary> appointments = context.AppointmentDiaries.Where(a => a.PatientId == id).ToList();
            var accountUsers = context.AccountUsers.Select(rr => new SelectListItem { Value = rr.AccountUserId.ToString(), Text = rr.FirstName + " " + rr.LastName }).ToList();
            ViewBag.AccountUsers = accountUsers;
            var location = context.Locations.Select(rr => new SelectListItem { Value = rr.LocationId.ToString(), Text = rr.LocationDesc }).ToList();
            ViewBag.Location = location;
            return PartialView("/Views/Patient/Appointment/_ViewAppointments.cshtml", appointments);
        }
    }

我的部分观点如下:

@foreach (var item in Model)
{
    <tr>
        <td>@Html.DisplayFor(x => item.DateTimeScheduled)</td>
        <td>@Html.DisplayFor(x => item.AppointmentLength)</td>
        <td>@Html.DisplayFor(x => item.AccountUser.FirstName) @Html.DisplayFor(x => item.AccountUser.LastName)</td>
        <td>@Html.DisplayFor(x => item.Location.LocationDesc)</td>
        <td>@Html.DropDownListFor(x => item.AttendedStatusId, (IEnumerable<SelectListItem>)ViewBag.AppointmentStatus, null, htmlAttributes: new { @class = "form-control", @id = "appointmentStatusId", onchange = "alert(this.options[this.selectedIndex].value);" })</td>
    </tr>
}

这是falling down，说明如下:

ObjectContext实例已被处置，不能再用于需要连接的操作。

我尝试使用。include在我的linq查询，但这没有工作。有什么想法吗，为什么这不起作用?

Answer 1

Alexander Derck的回答是，我需要在顶部的using语句中包含System.Data.Entity，然后下面的工作

    public ActionResult AppointmentsView(int id)
    {
        using (var context = new WaysToWellnessDB())
        {
            IEnumerable<AppointmentDiary> appointments = context.AppointmentDiaries.Include(p => p.AccountUser).Include(p => p.AttendedStatus).Include(p => p.Location).Where(a => a.PatientId == id).ToList();
            return PartialView("/Views/Patient/Appointment/_ViewAppointments.cshtml", appointments);
        }
    }

Answer 2

您已经实现了"using"块，一旦执行"using"块，它就会处理对象。因此，当您试图访问虚拟属性"item.AccountUser。FirstName"，因为上下文对象已经被处置，它抛出"ObjectContext实例已被处置"错误。正如Alexander Derck所发布的，使用include将解决这个问题，因为当上下文对象仍然存活时，您提前包含了所有必需的虚拟属性。