MVC EF似乎不能及时获取行更新

我正在跟踪用户是否可以使用自定义AuthorizeAttribute和数据库中保存其用户名和角色的表访问网站的某些页面。如果我更改用户的角色，无论是通过SQL还是通过应用程序页面，应用程序在一段时间内似乎都无法识别它，它会发生变化。它可能会立即收集，也可能需要5-10分钟甚至更长的时间。这样做的问题是，在他们的角色被更改后，他们仍然能够访问他们不应该被允许的页面。如果您查询所做更改的表，则更改将对数据库端产生影响。这似乎并没有发生在我的项目的其他地方。编辑另一个表似乎很好地反映了这些变化。

自定义授权属性:

private QIEducationEntities db = new QIEducationEntities();
public String Roles { get; set; }
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
    String userName = httpContext.User.Identity.Name.Split('''')[1];
    User user = db.Users.Include("UserRole").FirstOrDefault(u => u.UserName == userName);
    if (user != null) {
        String[] rolesList = Roles.Split(',');
        foreach (String role in rolesList)
        {
            if (user.UserRole.UserRole1 == role)
            {
                return true;
            }
        }
    }
    return false;
}
protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
    Uri requestUrl = filterContext.HttpContext.Request.UrlReferrer;
    if (requestUrl != null)
    {
        filterContext.Result = new RedirectResult(requestUrl.ToString());
        filterContext.Controller.TempData["PopupMessage"] = "You are not currently authorized to view that page.";
    }
    else
    {
        filterContext.Result = new RedirectToRouteResult(
                                    new RouteValueDictionary {
                                        { "action", "NotAuthorized" },
                                        { "controller", "Admin" }
                                    });
    }
}

编辑用户的角色动作(也显示属性):

//
//GET: Admin/EditUser
[AuthorizeUser(Roles = "Admin")]
public ActionResult EditUser(int id)
{
    User user = db.Users.Single(u => u.UserID == id);
    if (user == null)
    {
        return HttpNotFound();
    }
    ViewBag.Roles = new SelectList(db.UserRoles, "UserRoleID", "UserRole1", user.UserRole);
    return View(user);
}
//
//POST: Admin/EditUser
[AuthorizeUser(Roles = "Admin")]
[HttpPost]
public ActionResult EditUser(User user)
{
    if (ModelState.IsValid)
    {
        db.Users.Attach(user);
        db.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
        db.SaveChanges();
        return RedirectToAction("AllUsers");
    }
    ViewBag.Roles = new SelectList(db.UserRoles, "UserRoleID", "UserRole1", user.UserRole);
    return View(user);
}

视图(如果相关):

@using (Html.BeginForm())
{
    @Html.ValidationSummary(true)
    @Html.HiddenFor(model => model.UserID)
    <table class="table">
        <tr>
            <th class="table-row">
                User Name:
            </th>
            <td class="table-row">
                @Html.DisplayFor(model => model.UserName)
                @Html.HiddenFor(model => Model.UserName)
                @Html.ValidationMessageFor(model => model.UserName)
            </td>
        </tr>
        <tr>
            <th class="table-row">
                Role:
            </th>
            <td class="table-row">
                @Html.DropDownListFor(model => model.Role,
                    @ViewBag.Roles as SelectList, "",
                    new { @class = "chzn-select", data_placeholder = " -- Select Role -- " })
                @Html.ValidationMessageFor(model => model.UserRole)
            </td>
        </tr>
        <tr><td class="table-row-blank"></td></tr>
        <tr>
            <td class="table-row-button">
                <input class="button" type="submit" value="Submit" />
                <input type="button" class="button" value="Cancel" 
                    onclick="location.href='@Url.Action("AllUsers")'" />
            </td>
        </tr>
    </table>
}
@section Scripts {
    <script type="text/javascript">
        $(document).ready(function () {
            //DropDownList chosen plugin hook-up
            $('.chzn-select').prepend("<option></option>")
            $('.chzn-select').chosen({ width: "100%" });
        });
    </script>
}

所以，有没有什么东西稍微偏离编辑时，数据库上下文在我的项目没有捡起的变化?

或者在数据库上下文中"更新"值之间是否存在一定的时间间隔?

提前感谢。