Question

我不知道为什么我的createviewmodel允许使用Id和PublisherId的版本，唯一可见的应该是Title，ImageLink和两个列表（可见，未显示）

不仅看起来不正确，而且在尝试创建对象时很可能还会产生错误，给我null引用错误

http://oi64.tinypic.com/2luwitj.jpg

我的模特

public class Game
{ 
[Key]
public int Id { get; set; }
public string Title { get; set; }
public Publisher Publishers { get; set; }
public int PublisherID { get; set; }
public List<Category> Categories { get; set; }
public string ImageLink { get; set; }

public Game()
{
    Categories = new List<Category>();
}
}

我的视图模型

public class GameViewModel
{
public int Id { get;  set; }
public string Title { get;  set; }
public object Category { get;  set; }
public Publisher Publisher { get;  set; }
public string ImageLink { get;  set; }

public GameViewModel(int id, string title, List<Category> category, Publisher publisher, string imageLink)
{
    this.ID = id;
    this.Title = title;
    this.Category = category;
    this.Publisher = publisher;
    this.ImageLink = imageLink;
}

CreateViewModel

 public class CreateGameViewModel{

public Game Game { get; private set; }
public List<SelectListItem> Categories { get; private set; }
public List<SelectListItem> Publishers { get; private set; }
public int[] SelectedCategory { get; set; }
public CreateGameViewModel()
{
this.Game = new Game();
}

public CreateGameViewModel(List<Models.Category> categories, List<Models.Publisher> publishers) :this()
{
    Categories = categories.Select(c => new SelectListItem() { Text = c.Name, Value = c.Id.ToString() }).ToList();

    Publishers = publishers.Select(p => new SelectListItem() { Text = p.Name, Value = p.Id.ToString() }).ToList();
}
}

控制器

GET
 public ActionResult Create()
{
    var publishers = _db.Publishers.ToList();
    var categories = _db.Categories.ToList();
    var gameVM = new CreateGameViewModel(categories: categories, publishers: publishers);
    return View(gameVM);
}
 POST 
[HttpPost]
public ActionResult Create(CreateGameViewModel game)
{
    try
    {
        var categories = _db.Categories.Where(c => game.SelectedCategory.Contains(c.Id)).ToList();
        game.Game.Categories = categories;
        _db.Games.Add(game.Game);
        _db.SaveChanges();

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

然后创建视图

@model Project.ViewModels.CreateGameViewModel


<div class="row">
@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()

<div class="form-horizontal">
    <h4>CreateGameViewModel</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    @Html.EditorFor(model => model.Game)
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>
    </div>
</div>
    <div class="col-xs-6">
        <div class="row">
            <div class="form-group">
                <label class="control-label col-xs-3">Wydawcy</label>
                <div class="col-xs-9">
                    @Html.DropDownListFor(model => model.Game.PublisherId, Model.Publishers ?? new List<SelectListItem>(), "-Please select-")
                </div>
            </div>
        </div>
        <div class="row">
            <div class="form-group">
                <label class="control-label col-xs-3">Autorzy</label>
                <div class="col-xs-9">
                    @Html.ListBoxFor(model => model.SelectedCategory, Model.Categories)
                </div>
            </div>
        </div>

CreateXViewModel显示ID的编辑器

0 个答案: