Question

我目前正在通过MvcMusicStore教程第二次作为个人项目。这次代替实体框架我试图使用nHibernate以及使用Castle Windsor的一些IoC。

我遇到的第一个障碍与嵌套类和模型绑定有关。我能够显示专辑列表然后编辑它们。只要我编辑Title，Price或AlbumArtUrl字段，我也能够持久更改数据库。当我尝试编辑Artist或Genre字段时，会发生以下错误。

“无法更新'MvcMusicStore.Models.Album'类型的模型。”

在对UpdateModel的调用中发生此错误，所以我假设它与绑定有关但我完全难以理解如何继续。从我在StackOverflow和其他地方所做的搜索来看，这似乎是一个常见问题，但到目前为止我还没有找到解决方案。

我希望有人能够发现我在这里做错了什么并提出解决方案。

相册

public class Album
{
    public virtual int AlbumId { get; set; }
    public virtual Artist Artist { get; set; }
    public virtual Genre Genre { get; set; }
    public virtual string Title { get; set; }
    public virtual decimal Price { get; set; }
    public virtual string AlbumArtUrl { get; set; }
}

StoreManagerViewModel

public class StoreManagerViewModel
{
    public Album Album { get; set; }
    public IList<Artist> Artists { get; set; }
    public IList<Genre> Genres { get; set; }
}

Edit.aspx

<%@ Page Language="C#" MasterPageFile="/Views/Shared/Site.Master" 
   Inherits="System.Web.Mvc.ViewPage<MvcMusicStore.ViewModels.StoreManagerViewModel>" %>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
    Edit - <%: Model.Album.Title %>
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <h2>Edit Album</h2>

    <% using (Html.BeginForm()) {%>
        <%: Html.ValidationSummary(true) %>

    <fieldset>
        <legend>Edit Album</legend>
        <%: Html.EditorFor(model => model.Album, 
            new { Artists = Model.Artists, Genres = Model.Genres}) %>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>

    <% } %>

    <div>
        <%: Html.ActionLink("Back to List", "Index") %>
    </div>

</asp:Content>

Album.ascx

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<MvcMusicStore.Models.Album>" %>

<div class="editor-label">
    <%: Html.LabelFor(model => model.Title) %>
</div>
<div class="editor-field">
    <%: Html.TextBoxFor(model => model.Title) %>
    <%: Html.ValidationMessageFor(model => model.Title) %>
</div>

<div class="editor-label">
    <%: Html.LabelFor(model => model.Price) %>
</div>
<div class="editor-field">
    <%: Html.TextBoxFor(model => model.Price, String.Format("{0:F}", Model.Price)) %>
    <%: Html.ValidationMessageFor(model => model.Price) %>
</div>

<div class="editor-label">
    <%: Html.LabelFor(model => model.AlbumArtUrl) %>
</div>
<div class="editor-field">
    <%: Html.TextBoxFor(model => model.AlbumArtUrl) %>
    <%: Html.ValidationMessageFor(model => model.AlbumArtUrl) %>
</div>

<div class="editor-label">
    <%: Html.LabelFor(model => model.Artist)%>
</div>
<div class="editor-field">
    <%: Html.DropDownListFor(model => model.Artist, new SelectList(ViewData["Artists"] as IEnumerable, "ArtistId", "Name", Model.Artist))%>
</div>

<div class="editor-label">
    <%: Html.LabelFor(model => model.Genre)%>
</div>
<div class="editor-field">
    <%: Html.DropDownListFor(model => model.Genre, new SelectList(ViewData["Genres"] as IEnumerable, "GenreId", "Name", Model.Genre))%>
</div>

StoreManagerController

    public ActionResult Edit(int id)
    {
        var viewModel = new StoreManagerViewModel
        {
            Album = AlbumRepository.GetById(id),
            Genres = GenreRepository.GetAll().ToList(),
            Artists = ArtistRepository.GetAll().ToList(),
        };

        return View(viewModel);
    }

    [HttpPost, UnitOfWork]
    public ActionResult Edit(int id, FormCollection formValues)
    {
        var album = AlbumRepository.GetById(id);

        try
        {
            UpdateModel(album, "Album");
            AlbumRepository.SaveOrUpdate(album);

            return RedirectToAction("Index");
        }
        catch
        {
            var viewModel = new StoreManagerViewModel
            {
                Album = album,
                Genres = GenreRepository.GetAll().ToList(),
                Artists = ArtistRepository.GetAll().ToList(),
            };

            return View(viewModel);
        }
    }

更新1：

如果我在UpdateModel断点并查看ValueProvider.GetValue（“Album.Artist”），我可以看到更新的ArtistId。这告诉我，我完全误解了这应该如何运作。

我真的应该让UpdateModel处理它所喜欢的属性：

UpdateModel(album, "Album", new string[] { "Title", "Price", "AlbumArtUrl" });

然后根据ValueProvider中的ArtistId，GenreId自己提取对象，手动更新Artist和Genre属性？

更新2

修复了什么？

Album.ascx

<div class="editor-label">
    <%: Html.LabelFor(model => model.Artist)%>
</div>
<div class="editor-field">
    <%: Html.DropDownListFor(model => model.Artist, new SelectList(ViewData["Artists"] as IEnumerable, "ArtistId", "Name", Model.Artist.ArtistId))%>
</div>

<div class="editor-label">
    <%: Html.LabelFor(model => model.Genre)%>
</div>
<div class="editor-field">
    <%: Html.DropDownListFor(model => model.Genre, new SelectList(ViewData["Genres"] as IEnumerable, "GenreId", "Name", Model.Genre.GenreId))%>
</div>

StoreManagerController

UpdateModel(album, "Album", new string[] { "Title", "Price", "AlbumArtUrl" });
album.Artist = ArtistRepository.GetById(Int32.Parse(formValues["Album.Artist"]));
album.Genre = GenreRepository.GetById(Int32.Parse(formValues["Album.Genre"]));
AlbumRepository.SaveOrUpdate(album);

这是有效的，我不知道它是如何做这种事情的。如果不是，那么会有人把我弄好吗？

Answer 1

您必须在UpdateModel()

中提供您的逻辑

此外，如果您有强类型视图，则可以将模型用作控制器参数，而不是FormCollection。另外，最好排除已编辑相册的ID。

ActionResult Edit([Bind(Exclude = "AlbumId")]Album album)

你将从你的表单中获取相册的所有字段进行编辑。

关于您的代码：
现在我在你的代码中看到你在你的db

中通过id当前专辑获得了

 var album = AlbumRepository.GetById(id);

然后尝试用它做一些操作，并且不清楚如何从视图中绑定信息。

Answer 2

为了解决这个问题，我在ViewModel中创建了一个链接到相关对象的属性，然后对该属性进行了绑定：

<强>模型

public class User
{
    [Required(ErrorMessage = "Your first name is required.")]
    public string FirstName { get; set; }

    [Required(ErrorMessage = "Your last name is required.")]
    public string LastName { get; set; }        


    [Required(ErrorMessage = "A logon name is required.")]
    public string Logon { get; set; }

    [Required(ErrorMessage = "A password is required.")]
    public string Password { get; set; }

    [Required(ErrorMessage = "A role is required.")]
    public string Role { get; set; }

    [Required(ErrorMessage = "An airport is required.")]
    public Airport Airport { get; set; }

    [DisplayName("Is Active")]
    bool IsActive { get; set; }
}

查看

<div class="form-field"> <div class="field-label"><%= Html.LabelFor(m => m.User.Airport) %>:</div> <div class="field-input"><%= Html.DropDownListFor(m => m.UserAirportId, new SelectList(Model.Airports, "Id", "Name"))%></div> <div class="field-result"><%= Html.ValidationMessageFor(m => m.User.Airport) %></div> </div>

的视图模型

public class UserViewModel { public User User { get; set; } public List<Airport> Airports { get; set; } public List<String> Roles { get; set; } //Hack to get around non-binding of complex objects by UpdateModel public Guid UserAirportId { get { if (User != null && User.Airport != null) return User.Airport.Id; return Guid.Empty; } set { if (User == null) return; var airport = Airports.Where(m => m.Id == value).FirstOrDefault(); if (airport == null) return; User.Airport = airport; } } }

ASP.NET MVC2中嵌套属性的UpdateModel

2 个答案:

<强>模型

查看

的视图模型