asp.net-mvc - MVC 发布复杂对象列表

Question

我有一个包含问题列表的 FeedbackViewModel:

public class FeedbackViewModel
{
    public List<QuestionViewModel> Questions { get; set; }
}

这个 QuestionViewModel 是一个对象，可以被 5 种不同类型的问题继承

public class QuestionViewModel
{
    public string QuestionText { get; set; }
    public string QuestionType { get; set; }
}

继承问题类型之一的示例:

public class SingleQuestionViewModel : QuestionViewModel
{
    public string AnswerText { get; set; }
}

在 HttpGet的 Index Controller 中的操作我从数据库中获取问题并在 FeedbackViewModel 的问题列表中添加正确的问题类型然后我在 View 中渲染这个模型:

@using (Html.BeginForm())
{
    //foreach (var item in Model.Questions)
    for (int i = 0; i < Model.Questions.Count; i++)
    {
        <div class="form-group">
            @Html.DisplayFor(modelItem => Model.Questions[i].QuestionText, new { @class = "control-label col-md-4" })
            <div class="col-md-6">
                @if (Model.Questions[i].QuestionType == "Single")
                {
                    @Html.EditorFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
                }
                else if (Model.Questions[i].QuestionType == "Multiple")
                {
                    @Html.TextAreaFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
                }
                else if (Model.Questions[i].QuestionType == "SingleSelection")
                {
                    @Html.RadioButtonForSelectList(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleSelectionQuestionViewModel).SelectedAnswer,
                                                                (Model.Questions[i] as OpenDataPortal.ViewModels.SingleSelectionQuestionViewModel).SelectionAnswers)
                }
                else if (Model.Questions[i].QuestionType == "MultipleSelection")
                {
                    @Html.CustomCheckBoxList((Model.Questions[i] as OpenDataPortal.ViewModels.MultipleSelectionQuestionViewModel).AvailableAnswers)
                }
                else if (Model.Questions[i].QuestionType == "UrlReferrer")
                {
                    @Html.EditorFor(modelItem => (Model.Questions[i] as OpenDataPortal.ViewModels.SingleQuestionViewModel).AnswerText)
                }
            </div>
        </div>
        <br />
    }

    <br />
    <button type="submit">Submit</button>
}

现在，我根本无法让它在模型中发布问题列表。甚至可以发布不同对象类型的列表吗？

编辑:以下是我使用 Fiddler 发现的帖子中的数据列表:

Answer 1

经过大量研究，我找到了两种解决方案:

一种是编写具有硬编码 ID 和名称的 HTML

二是将您的 ICollection/IEnumerable 转换为数组或列表(即 IList 带有“索引”的东西)，并在 Controller POST 操作中的 BindingModel 中有一个数组对象。

感谢 Phil Haack (@haacked) 2008 年的博文 http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx/
这仍然与今天默认的 ModelBinder 如何为 MVC 工作有关。
(注意:Phil 文章中示例项目和扩展方法的链接已损坏)

启发我的 HTML 片段:

<form method="post" action="/Home/Create">
    <input type="hidden" name="products.Index" value="cold" />
    <input type="text" name="products[cold].Name" value="Beer" />
    <input type="text" name="products[cold].Price" value="7.32" />

    <input type="hidden" name="products.Index" value="123" />
    <input type="text" name="products[123].Name" value="Chips" />
    <input type="text" name="products[123].Price" value="2.23" />

    <input type="submit" />
</form>

Post 数组看起来有点像:

products.Index=cold&products[cold].Name=Beer&products[cold].Price=7.32&products.Index=123&products[123].Name=Chips&products[123].Price=2.23

模型:

public class CreditorViewModel
{
    public CreditorViewModel()
    {
        this.Claims = new HashSet<CreditorClaimViewModel>();
    }
    [Key]
    public int CreditorId { get; set; }
    public string Comments { get; set; }
    public ICollection<CreditorClaimViewModel> Claims { get; set; }
    public CreditorClaimViewModel[] ClaimsArray { 
        get { return Claims.ToArray(); }
    }
}

public class CreditorClaimViewModel
{
    [Key]
    public int CreditorClaimId { get; set; }
    public string CreditorClaimType { get; set; }
    [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:N2}")]
    public Decimal ClaimedTotalAmount { get; set; }
}

Controller 获取:

public async Task<ActionResult> Edit(int id)
    {
        var testmodel = new CreditorViewModel
        {
            CreditorId = 1,
            Comments = "test",
            Claims = new HashSet<CreditorClaimViewModel>{
                new CreditorClaimViewModel{ CreditorClaimId=1, CreditorClaimType="1", ClaimedTotalAmount=0.00M},
                new CreditorClaimViewModel{ CreditorClaimId=2, CreditorClaimType="2", ClaimedTotalAmount=0.00M},
            }
        };
        return View(model);
    }

编辑.cshtml:

@Html.DisplayNameFor(m => m.Comments)
@Html.EditorFor(m => m.Comments)

<table class="table">
    <tr>
        <th>
            @Html.DisplayNameFor(m => Model.Claims.FirstOrDefault().CreditorClaimType)
        </th>
        <th>
            @Html.DisplayNameFor(m => Model.Claims.FirstOrDefault().ClaimedTotalAmount)
        </th>
    </tr>        
<!--Option One-->
@foreach (var item in Model.Claims)
{
    var fieldPrefix = string.Format("{0}[{1}].", "Claims", item.CreditorClaimId);
    <tr>
        <td>
            @Html.DisplayFor(m => item.CreditorClaimType)
        </td>
        <td>
        @Html.TextBox(fieldPrefix + "ClaimedTotalAmount", item.ClaimedTotalAmount.ToString("F"),
        new
        {
            @class = "text-box single-line",
            data_val = "true",
            data_val_number = "The field ClaimedTotalAmount must be a number.",
            data_val_required = "The ClaimedTotalAmount field is required."
        })
        @Html.Hidden(name: "Claims.index", value: item.CreditorClaimId, htmlAttributes: null)
        @Html.Hidden(name: fieldPrefix + "CreditorClaimId", value: item.CreditorClaimId, htmlAttributes: null)
        </td>
    </tr>
    }
</table>    
<!--Option Two-->
@for (var itemCnt = 0; itemCnt < Model.ClaimsArray.Count(); itemCnt++)
{
    <tr>
        <td></td>
        <td>
            @Html.TextBoxFor(m => Model.ClaimsArray[itemCnt].ClaimedTotalAmount)
            @Html.HiddenFor(m => Model.ClaimsArray[itemCnt].CreditorClaimId)
    </td></tr>
}

表单在 Controller 中处理:

岗位型号:

public class CreditorPostViewModel
{
    public int CreditorId { get; set; }
    public string Comments { get; set; }
    public ICollection<CreditorClaimPostViewModel> Claims { get; set; }
    public CreditorClaimPostViewModel[] ClaimsArray  { get; set; }
}

public class CreditorClaimPostViewModel
{
    public int CreditorClaimId { get; set; }
    public Decimal ClaimedTotalAmount { get; set; }
}

Controller :

[HttpPost]
    public ActionResult Edit(int id, CreditorPostViewModel creditorVm)
    {
        //...