Question

我有一个局部视图用于编辑集合（在这里我已将其中大部分截断了）：

@using CustomSurveyTool.Models
@model Basiclife
<div class="editorRow">
    @using (Html.BeginCollectionItem(""))
    {
        <div class="form-horizontal">
            <div class="row">
                @Html.ValidationSummary(true, "", new { @class = "text-danger" })

                <div class="col-md-2">
                    @Html.LabelFor(model => model.Plantype, htmlAttributes: new { @class = "control-label" })

                    @Html.EditorFor(model => model.Plantype, new { htmlAttributes = new { @class = "form-control" } })
                    @Html.ValidationMessageFor(model => model.Plantype, "", new { @class = "text-danger" })
                </div>
                <div class="col-md-1">
                    <a href="#" class="deleteRow">X</a>
                </div>
            </div>
        </div>
    }
</div>

这是包装视图的一部分：

@using CustomSurveyTool.Models
@model IEnumerable<Basiclife>
@{
    ViewBag.Title = "CreateBasicLifeResponse";
}

<h2>Basic Life Insurance Plans</h2>
<div id="planList">
    @using (Html.BeginForm())
    {
        <div id="editorRows">
            @foreach (var item in Model)
            {
                @Html.Partial("_BasicLifeResponse", item)
                }
        </div>
        @Html.ActionLink("Add", "BasicLifeResponse", null, new { id = "addItem", @class = "button" });
        <input type="submit" value="submit" />
    }
</div>

回发给该控制器的人

    [HttpPost]
    public ActionResult CreateBasicLifeResponse(IEnumerable<Basiclife> model)
    {

        foreach(var item in model)
        {
            string currentUserId = User.Identity.GetUserId();
            Response targetresponse = db.response.FirstOrDefault(x => x.Userid == currentUserId);
            int responseid = targetresponse.Id;
            item.ResponseId = responseid;
            db.basiclife.Add(item);
            db.SaveChanges();
        }

        List<Basiclife> basiclife = new List<Basiclife>();
        return View(model);
    }

提交表单后，我在foreach(var item in model)上收到NullReferenceException。可能是什么原因造成的？

Answer 1

您需要遵循MVC命名约定，该约定涉及在Razor视图中使用带有索引的for循环，而不是foreach。查看这篇文章： How to pass IEnumerable list to controller in MVC including checkbox state?。我建议使用本文中介绍的“编辑器模板”方法，它与您当前的PartialView方法最相似。

MVC可变长度收集模型为空

1 个答案: