ObjectContext中实例已被释放，并可以不再被用于需要连接的操作 [英] The ObjectContext instance has been disposed and can no longer be used for operations that require a connection

问题描述

我有这样的看法：

@model MatchGaming.Models.ProfileQuery
@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>    
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>

@using (Html.BeginForm("Results", "Profiles")) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>ProfileQuery</legend>
        @Html.EditorFor(model=>model.SearchString)
        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

我有这个控制器的HttpPost：

I have this controller for the HttpPost:

[HttpPost]
public ActionResult Results(ProfileQuery profileQuery)
{
    Debug.Write(profileQuery.SearchString);
    using(var db = new MatchGamingEntities())
    {
        var SearchUserName = db.Users.SingleOrDefault(a=> a.UserName.Contains(profileQuery.SearchString));
        var Users = from m in db.Users
                    join m2 in db.MyProfiles on m.UserId equals m2.UserId
                    where m.UserName == SearchUserName.UserName
                    select new UserViewModel
                    {
                        UserName = m.UserName,
                        LastActivityDate = m.LastActivityDate,
                        Address = m2.Address,
                        City = m2.City,
                        State = m2.State,
                        Zip = m2.Zip
                    };

        return View(Users.AsEnumerable());
    }
}

下面是查看结果：

@model IEnumerable<MatchGaming.Models.UserViewModel>    
@{
    ViewBag.Title = "Results";
}

<h2>Results</h2>

<fieldset>
    <legend>UserViewModel</legend>
    @foreach (var item in Model){
    <div class="display-label">UserName</div>
    <div class="display-field">@item.UserName</div>

    <div class="display-label">LastActivityDate</div>
    <div class="display-field">@String.Format("{0:g}", item.LastActivityDate)</div>

    <div class="display-label">Address</div>
    <div class="display-field">@item.Address</div>

    <div class="display-label">City</div>
    <div class="display-field">@item.City</div>

    <div class="display-label">State</div>
    <div class="display-field">@item.State</div>

    <div class="display-label">Zip</div>
    <div class="display-field">@item.Zip</div>
    }
</fieldset>

我不断收到此错误：

I keep getting this error:

的ObjectContext的实例已被释放，并可以不再被用于需要连接的操作。

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

我想不出为什么。

推荐答案

我猜测的问题是，你的LINQ查询的执行被推迟，直到开始访问它们在你的看法。此时分贝已被释放。

I am guessing that the problem is that the execution of your LINQ query has been deferred until starting to access them on your view. At this point db has already been disposed.

试试这个：

return View(Users.ToList());

新增了ToList（）的

这将处理前分贝强制从数据库的获取。

That will force the fetch from the DB before disposing db.

这篇关于ObjectContext中实例已被释放，并可以不再被用于需要连接的操作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！