json - 在执行 ajax 调用时序列化类型的对象时检测到循环引用

标签 json ajax asp.net-mvc

在我看来，我使用的是 Viewmodel，并且我有一个只有一个接受日期的文本框(不是 Viewmodel 的一部分)和 3 个表格的表单。默认情况下在页面加载时.. 表中填充了基于今天日期的数据(您可以在下面的 Controller 代码中看到)，但是如果用户选择一个日期并单击搜索按钮，那么我希望更改表数据没有根据他们选择的日期刷新页面。

@using (Html.BeginForm())
{
    <div class="form-group mb-3 mt-3" style="margin-right: -1.3%;">
        <div class="input-group col-md-3 offset-md-9">
            @Html.TextBox("detailsDate", null, new { id = "Details-Date", @class = "form-control datetimepicker" })
            <div class="input-group-append">
                <button id="Details-Date-Btn" type="submit" class="btn btn-outline-primary"><span class="fa fa-search"></span></button>
            </div>
        </div>
    </div>
}

我想做的是，如果用户选择日期并点击搜索按钮。我希望页面不刷新，并且表格数据已根据日期更改。截至目前，我得到:

A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.tbl_WeighAssc_8AA7AB5F9DAB261D5142F1D5F5BA6705A588A5AAD2D369FBD4B4BC1BBE0487D4'.

View 模型

public class PersonnelDetailsVm
{
    private static ConnectionString db = new ConnectionString();
    public PersonnelDetailsVm()
    {
        CurrentWeekDates = new List<DateTime>();
        WeighAssociations = new List<tbl_WeighAssc>();
        ArrestAssociations = new List<tbl_TEUArrestAssc>();
        InspectionAssociations = new List<tblTEUInspectionAssc>();
    }
    public string IBM { get; set; }

    [Display(Name = "Name")]
    public string UserName { get; set; }

    public bool Active { get; set; }

    public List<DateTime> CurrentWeekDates { get; set; }
    public List<tbl_WeighAssc> WeighAssociations { get; set; }
    public List<tbl_TEUArrestAssc> ArrestAssociations { get; set; }
    public List<tblTEUInspectionAssc> InspectionAssociations { get; set; }
    public List<code_WeighLocation> WeighLocations => db.code_WeighLocation.ToList();
    public List<code_ArrestType> ArrestTypes => db.code_ArrestType.ToList();
    public List<code_InspectionLevel> InspectionLevels => db.code_InspectionLevel.ToList();
}

Ajax :

// Submission
//var redirectUrl = '@Url.Action("Index", "Personnels")';
var settings = {};
settings.baseUri = '@Request.ApplicationPath';
var infoGetUrl = "";
if (settings.baseUri === "/AppName") {
    infoGetUrl = settings.baseUri + "/Personnels/Details/";
} else {
    infoGetUrl = settings.baseUri + "Personnels/Details/";
}

$("#Details-Date-Btn").click(function() {
    $.ajax({
        url: infoGetUrl,
        method: "POST",
        data: $("form").serialize(),
        success: function(response) {
            console.log("success");
            $("body").html(response);
        },
        error: function(jqXHR, textStatus, errorThrown) {
            console.log(jqXHR);
        }
    });
});

Controller :

public ActionResult Details(string id, string detailsDate)
{
    if (id == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }

    tblPersonnel tblPersonnel = db.tblPersonnels.Find(id);

    if (tblPersonnel == null)
    {
        return HttpNotFound();
    }

    Mapper.Initialize(config => config.CreateMap<tblPersonnel, PersonnelDetailsVm>());
    PersonnelDetailsVm person = Mapper.Map<tblPersonnel, PersonnelDetailsVm>(tblPersonnel);

    var employeeData = EmployeeData.GetEmployee(person.IBM);

    person.UserName =
        $"{ConvertRankAbbr.Conversion(employeeData.Rank_Position)} {employeeData.FirstName} {employeeData.LastName}";

    if (string.IsNullOrWhiteSpace(detailsDate))
    {
        var startOfWeek = DateTime.Today.AddDays((int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek -
                                                 (int)DateTime.Today.DayOfWeek);
        person.CurrentWeekDates = Enumerable.Range(0, 7).Select(i => startOfWeek.AddDays(i)).ToList();
        var teuFormIds = db.tbl_TEUForm
            .Where(x => person.CurrentWeekDates.Contains(x.EventDate) && x.PersonnelIBM == person.IBM).Select(t => t.Id).ToList();

        person.WeighAssociations = db.tbl_WeighAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.ArrestAssociations = db.tbl_TEUArrestAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.InspectionAssociations =
            db.tblTEUInspectionAsscs.Where(x => teuFormIds.Contains(x.TEUId)).ToList();


        return View(person);

    }
    else
    {
        var paramDate = DateTime.ParseExact(detailsDate, "MM/dd/yyyy", CultureInfo.CurrentCulture);

        var startOfWeek = paramDate.AddDays((int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek -
                                                 (int)paramDate.DayOfWeek);
        person.CurrentWeekDates = Enumerable.Range(0, 7).Select(i => startOfWeek.AddDays(i)).ToList();
        var teuFormIds = db.tbl_TEUForm
            .Where(x => person.CurrentWeekDates.Contains(x.EventDate) && x.PersonnelIBM == person.IBM).Select(t => t.Id).ToList();

        person.WeighAssociations = db.tbl_WeighAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.ArrestAssociations = db.tbl_TEUArrestAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.InspectionAssociations =
            db.tblTEUInspectionAsscs.Where(x => teuFormIds.Contains(x.TEUId)).ToList();

        return Json(person, JsonRequestBehavior.AllowGet);
    }

}

因此，如果 actionresult 的参数 detailsDate 不为 null，则它会进入返回 JSON 对象的 else 语句。当调试完成并返回 View 时，我收到上面发布的错误。

有没有办法用我从 ajax 调用返回的内容替换 View 中的模型，这样表格就可以基于正确的日期而无需刷新页面？

非常感谢任何帮助。

更新

根据下面的回答，我将 Controller 方法中的 else 语句编辑为:

Controller 

else
{
    var paramDate = DateTime.ParseExact(detailsDate, "MM/dd/yyyy", CultureInfo.CurrentCulture);

    var startOfWeek = paramDate.AddDays((int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek -
                                             (int)paramDate.DayOfWeek);
    person.CurrentWeekDates = Enumerable.Range(0, 7).Select(i => startOfWeek.AddDays(i)).ToList();
    var teuFormIds = db.tbl_TEUForm
        .Where(x => person.CurrentWeekDates.Contains(x.EventDate) && x.PersonnelIBM == person.IBM).Select(t => t.Id).ToList();

    person.WeighAssociations = db.tbl_WeighAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
    person.ArrestAssociations = db.tbl_TEUArrestAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
    person.InspectionAssociations =
        db.tblTEUInspectionAsscs.Where(x => teuFormIds.Contains(x.TEUId)).ToList();

    JsonConvert.DefaultSettings = () => new JsonSerializerSettings()
    {
        PreserveReferencesHandling = PreserveReferencesHandling.All,
        ReferenceLoopHandling = ReferenceLoopHandling.Ignore
    };

    var jsonStr = JsonConvert.SerializeObject(person);

    return Json(jsonStr, "text/plain");
}

我的 jQuery/Ajax 还是一样:

$("#Details-Date-Btn").click(function() {
    $.ajax({
        url: infoGetUrl,
        data: $("form").serialize(),
        success: function(response) {
            console.log("success");
            console.log(response);
            $("body").html(response);
        },
        error: function(jqXHR, textStatus, errorThrown) {
            console.log(jqXHR);
        }
    });
});

But now, when the date is selected I am being returned to a page that shows the Json like a plain text file and losing the HTML and CSS like a normal view.

这是选择日期并单击按钮时返回的内容。

enter image description here

此外，当我选择一个日期并单击该日期的按钮以发送到 Controller 时检查控制台时，我看到了:

enter image description here

更新 2

这是我的一张 table ..其他的都是相同的设置:

<table class="table table-bordered">
    <thead>
        <tr>
            <th></th>
            @foreach (var date in Model.CurrentWeekDates)
            {
                <th class="text-center">@date.ToString("ddd") <br /> @date.ToShortDateString()</th>
            }
                <th class="text-center table-success">Total For Week</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var weighLocation in Model.WeighLocations)
        {
            <tr class="text-center">
                <td class="table-dark">@weighLocation.Weigh_Location</td>
                @foreach (var date in Model.CurrentWeekDates)
                {
                    if (Model.WeighAssociations.Any(x => x.tbl_TEUForm.EventDate == date && x.WeighLocationId == weighLocation.ID))
                    {
                        <td>@Model.WeighAssociations.Single(x => x.tbl_TEUForm.EventDate == date && x.WeighLocationId == weighLocation.ID).OccurenceCount</td>
                    }
                    else
                    {
                        <td>0</td>
                    }

                }
                <td class="table-success font-weight-bold">@Model.WeighAssociations.Where(x => x.WeighLocationId == weighLocation.ID).Sum(x => x.OccurenceCount)</td>
            </tr>
        }
    </tbody>
</table>

最佳答案

据我从您的问题中可以看出，要解决它，您可以执行以下步骤:

1- View

添加局部 View (_Detail.cshtml)

您需要一个部分 View ，例如_Detail，其中包含您的表，如下所示:

@model PersonnelDetailsVm  

<table class="table table-bordered">
    <thead>
        <tr>
            <th></th>
            @foreach (var date in Model.CurrentWeekDates)
            {
                <th class="text-center">@date.ToString("ddd") <br /> @date.ToShortDateString()</th>
            }
                <th class="text-center table-success">Total For Week</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var weighLocation in Model.WeighLocations)
        {
            <tr class="text-center">
                <td class="table-dark">@weighLocation.Weigh_Location</td>
                @foreach (var date in Model.CurrentWeekDates)
                {
                    if (Model.WeighAssociations.Any(x => x.tbl_TEUForm.EventDate == date && x.WeighLocationId == weighLocation.ID))
                    {
                        <td>@Model.WeighAssociations.Single(x => x.tbl_TEUForm.EventDate == date && x.WeighLocationId == weighLocation.ID).OccurenceCount</td>
                    }
                    else
                    {
                        <td>0</td>
                    }

                }
                <td class="table-success font-weight-bold">@Model.WeighAssociations.Where(x => x.WeighLocationId == weighLocation.ID).Sum(x => x.OccurenceCount)</td>
            </tr>
        }
    </tbody>
</table>

2- Controller

返回局部 View

您应该在 Controller 中填充模型并将其传递给分部 View 。

public ActionResult Details(string id, string detailsDate)
{
    if (id == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }

    tblPersonnel tblPersonnel = db.tblPersonnels.Find(id);

    if (tblPersonnel == null)
    {
        return HttpNotFound();
    }

    Mapper.Initialize(config => config.CreateMap<tblPersonnel, PersonnelDetailsVm>());
    PersonnelDetailsVm person = Mapper.Map<tblPersonnel, PersonnelDetailsVm>(tblPersonnel);

    var employeeData = EmployeeData.GetEmployee(person.IBM);

    person.UserName =
        $"{ConvertRankAbbr.Conversion(employeeData.Rank_Position)} {employeeData.FirstName} {employeeData.LastName}";

    if (string.IsNullOrWhiteSpace(detailsDate))
    {
        var startOfWeek = DateTime.Today.AddDays((int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek -
                                                 (int)DateTime.Today.DayOfWeek);
        person.CurrentWeekDates = Enumerable.Range(0, 7).Select(i => startOfWeek.AddDays(i)).ToList();
        var teuFormIds = db.tbl_TEUForm
            .Where(x => person.CurrentWeekDates.Contains(x.EventDate) && x.PersonnelIBM == person.IBM).Select(t => t.Id).ToList();

        person.WeighAssociations = db.tbl_WeighAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.ArrestAssociations = db.tbl_TEUArrestAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.InspectionAssociations =
            db.tblTEUInspectionAsscs.Where(x => teuFormIds.Contains(x.TEUId)).ToList();


        // return View(person); 



    }
    else
    {
        var paramDate = DateTime.ParseExact(detailsDate, "MM/dd/yyyy", CultureInfo.CurrentCulture);

        var startOfWeek = paramDate.AddDays((int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek -
                                                 (int)paramDate.DayOfWeek);
        person.CurrentWeekDates = Enumerable.Range(0, 7).Select(i => startOfWeek.AddDays(i)).ToList();
        var teuFormIds = db.tbl_TEUForm
            .Where(x => person.CurrentWeekDates.Contains(x.EventDate) && x.PersonnelIBM == person.IBM).Select(t => t.Id).ToList();

        person.WeighAssociations = db.tbl_WeighAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.ArrestAssociations = db.tbl_TEUArrestAssc.Where(x => teuFormIds.Contains(x.TEUId)).ToList();
        person.InspectionAssociations =
            db.tblTEUInspectionAsscs.Where(x => teuFormIds.Contains(x.TEUId)).ToList();

        // return Json(person, JsonRequestBehavior.AllowGet);
    }

    // return PartialView with the person model
    return PartialView("_Detail", person);

}

正如您在上面的代码中看到的，您应该在代码中注释两行:

// return View(person); 
// return Json(person, JsonRequestBehavior.AllowGet);

3- Ajax调用

获取局部 View 并通过它填写表单

您不需要对 ajax 调用进行任何更改，您可以这样做:

$("#Details-Date-Btn").click(function() {
    $.ajax({
        url: infoGetUrl,
        method: "POST",
        data: $("form").serialize(),
        success: function(response) {
            console.log("success");
            $("body").html(response);
        },
        error: function(jqXHR, textStatus, errorThrown) {
            console.log(jqXHR);
        }
    });
});

response 这种方式是来自局部 View 的 html，它具有您设计的所有类。

关于json - 在执行 ajax 调用时序列化类型的对象时检测到循环引用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52317167/

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