从jquery向控制器发送POST请求时发生500内部服务器错误

控制器代码

public ActionResult SearchByUPC_Name(String keyword)
{
    using (DbPOSEntities db = new DbPOSEntities())
    {
        var CompanyID = ((UserModel)Session["User"]).CompanyID;
        var items = db.tblItems.Where(i => i.CompanyID == CompanyID 
                        && i.IsDeleted == false 
                        && (i.UPC == keyword || i.Name.Contains(keyword))).ToList();
        return Json(new { Success = true, Items = items });
    }
}

$.ajax({
    url: "/Item/SearchByUPC_Name",
    type: "POST",
    async: true,
    contentType: "application/json; charset=utf-8",
    data: JSON.stringify({ "keyword": searchStr }),
    dataType: "json",
    success: function (response) {
        debugger;
        if (response.Success) {
            console.log('ok');
        }
        else {
            console.log('not ok');
        }
    },
    error: function (err) {
        alert(err.statusText);
    }
});

Js代码

public ActionResult SearchByUPC_Name(String keyword)
{
    using (DbPOSEntities db = new DbPOSEntities())
    {
        var CompanyID = ((UserModel)Session["User"]).CompanyID;
        var items = db.tblItems.Where(i => i.CompanyID == CompanyID 
                        && i.IsDeleted == false 
                        && (i.UPC == keyword || i.Name.Contains(keyword))).ToList();
        return Json(new { Success = true, Items = items });
    }
}

$.ajax({
    url: "/Item/SearchByUPC_Name",
    type: "POST",
    async: true,
    contentType: "application/json; charset=utf-8",
    data: JSON.stringify({ "keyword": searchStr }),
    dataType: "json",
    success: function (response) {
        debugger;
        if (response.Success) {
            console.log('ok');
        }
        else {
            console.log('not ok');
        }
    },
    error: function (err) {
        alert(err.statusText);
    }
});

---

我收到此错误：500内部服务器错误：ObjectContext实例已被释放，无法再用于需要连接的操作。

由于实体框架的延迟加载属性，您使用wrap的

可能会导致此错误。它在返回实体之前处理上下文

using (DbPOSEntities db = new DbPOSEntities())
    {
        var CompanyID = ((UserModel)Session["User"]).CompanyID;
        var items = db.tblItems.Where(i => i.CompanyID == CompanyID 
                        && i.IsDeleted == false 
                        && (i.UPC == keyword || i.Name.Contains(keyword))).ToList();
        return Json(new { Success = true, Items = items });
    }

您可以使用

wrap删除

，以使用快速加载来避免您面临的错误：

DbPOSEntities db = new DbPOSEntities();
var CompanyID = ((UserModel)Session["User"]).CompanyID;
var items = db.tblItems.Where(i => i.CompanyID == CompanyID 
                    && i.IsDeleted == false 
                    && (i.UPC == keyword || i.Name.Contains(keyword))).ToList();
return Json(new { Success = true, Items = items });

不要使用

将查询包装在

中。有关详细说明，请参阅。