Question

我有ViewModel

public class Magazine_ViewModel
{
    public int MagId { get; set; }
    public string MagNo { get; set; }
    public IEnumerable<Titles_ViewModel> Titles { get; set; }
}

public class Titles_ViewModel
{
    public int TitleId { get; set; }
    public string TitleName { get; set; }
    public int pos { get; set; }
}

在Controller中

我喜欢这个

        var viewModel = new Magazine_ViewModel
        {
            Titles = numberTitles
                .Select(c => new Titles_ViewModel
                {
                    TitleId = c.TitleId,
                    TitleName = c.Title.TitleText,
                    pos=c.position
                }).ToList()
        };                    
        viewModel.MagNo = magazine.MagNo.ToString();
        viewModel.MagId = magazine.Id;

当我检查viewModel.Titles有n条记录是正确的。现在在视图部分

     <div class="editor-label">
        @Html.LabelFor(model => model.MagNo)
    </div>
    <div class="editor-field">
     @Html.EditorFor(model => model.MagNo)
    </div>

    <div class="editor-field">
     @Html.ListBox("wholeTitles")
     <input type="button" name="add" id="add" value="add" onclick="addValue()" /><input type="button" name="remove" id="remove" value="remove"  onclick="removeValue()"/>
      @Html.ListBoxFor(model => model.Titles, new SelectList(Model.Titles, "TitleId", "TitleName"))
    </div>
     <p>
        <input type="submit" value="Save" />
    </p>

我将第一个ListBox（wholeTitles）中的新标题添加到第二个ListBox（标题）。现在按下提交按钮，我想将新标题添加到数据库中。

这就是我在Post Action中所做的事情

     [HttpPost]
    public ActionResult EditTitle(Magazine_ViewModel magazineViewModel)
    {

        if (ModelState.IsValid)
        {
            var magazineTitles = new Magazine
            {
                Id = magazineViewModel.MagId,
                NumberTitles = new List<NumberTitle>()
            };

            foreach (var numberTitle in magazineViewModel.Titles)
            {

                    NumberTitle newNumberTitle = new NumberTitle();
                    newNumberTitle.MagazineId = magazineViewModel.MagId;
                    newNumberTitle.TitleId = numberTitle.TitleId;
                    newNumberTitle.position = 0;
                    unitOfWork.NumberTitleRepository.Insert(newNumberTitle);

            }
        }
        return View();
    }

但是magazineViewModel.Titles显示为null，我不知道应该检查它为什么它是null值。

Answer 1

您的值不会回发到服务器。在视图中使用以下内容。这应该将标题发布回同一ViewModel中的服务器

    for (var i = 0; i < Model.Titles.Count(); i++)
    {
        @Html.HiddenFor(m => m.Titles[i].TitleId)
        @Html.HiddenFor(m => m.Titles[i].TitleName)
    }

IEnumerable属性无法返回值

1 个答案: