c# - Razor 呈现新闻和类别，多种模型

我正在创建新闻页面。我有新闻模型，新闻有一个类别。类别来自数据库。我希望能够创建新闻并为新闻分配类别。以下是我尝试执行的操作。问题是我试图为类别创建一个下拉列表，一旦填写表格，它将被提交以保存在数据库中。

这是错误：我正在传递IEnumerable<SelectListItem> categoriesList进行查看，但是它正在等待新闻模型。如何在一个视图中使用多个模型？我如何解决下面的代码，使其可以工作？

@model App.Models.News

@{
    ViewBag.Title = "Create";
}

<h2>Create news</h2>

@using (Html.BeginForm()) {
    <div>
        <fieldset>
            <legend>Category Information</legend>

            <div class="editor-label">
                @Html.LabelFor(m => m.Title)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(m => m.Title)
                @Html.ValidationMessageFor(m => m.Title)
            </div>

            <div class="editor-label">
                @Html.LabelFor(m => m.Category)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(m => m.Category)
                @Html.ValidationMessageFor(m => m.Category)
            </div>

            <div class="editor-label">
                @Html.LabelFor(m => m.NewsContent)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(m => m.NewsContent)
                @Html.ValidationMessageFor(m => m.NewsContent)
            </div>
            <p>
                <input type="submit" value="Log On" />
            </p>
        </fieldset>
    </div>
}

        public ActionResult Create()
        {
            IList<Category> categories;
            using (var session = NHibernateHelper.OpenSession())
            {
                using (var tx = session.BeginTransaction())
                {
                    categories = session.CreateCriteria(typeof(Category)).List<Category>();
                    tx.Commit();
                }

            }

            IEnumerable<SelectListItem> categoriesList = categories.Select(category => new SelectListItem() { Text = category.Name, Value = category.Id.ToString() });

            return View(categoriesList);
        }

最佳答案

如果您的视图需要News对象，则必须将News对象传递给它。如果要使用多个模型，则可以创建一个视图模型：

public class NewsViewModel
{
    public string SelectedCategoryId { get; set; }
    public IEnumerable<SelectListItem> Categories { get; set; }

    ... put any properties that your view might require
}

然后将您的视图强烈键入NewsViewModel，并让控制器操作将其实例传递给该视图。

您应该将News实例传递给视图：

public ActionResult Create()
{
    IList<Category> categories;
    using (var session = NHibernateHelper.OpenSession())
    using (var tx = session.BeginTransaction())
    {
        categories = session.CreateCriteria(typeof(Category)).List<Category>();
        tx.Commit();
    }
    IEnumerable<SelectListItem> categoriesList = categories.Select(category => new SelectListItem() { Text = category.Name, Value = category.Id.ToString() });
    var news = new NewsViewModel
    {
        Categories = categoriesList
    };
    return View(news);
}

并且在您看来：

@model App.Models.NewsViewModel

另一种可能性（我不推荐）是使用ViewBag：

public ActionResult Create()
{
    IList<Category> categories;
    using (var session = NHibernateHelper.OpenSession())
    using (var tx = session.BeginTransaction())
    {
        categories = session.CreateCriteria(typeof(Category)).List<Category>();
        tx.Commit();
    }
    IEnumerable<SelectListItem> categoriesList = categories.Select(category => new SelectListItem() { Text = category.Name, Value = category.Id.ToString() });
    ViewBag.Categories = categoriesList;

    // or fetch from DB or whatever
    var news = new News();
    return View(news);
}

并在视图中：

@model App.Models.News

@{
    ViewBag.Title = "Create";
}

<h2>Create news</h2>

@using (Html.BeginForm()) {
    <div>
        <fieldset>
            <legend>Category Information</legend>

            <div class="editor-label">
                @Html.LabelFor(m => m.Title)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(m => m.Title)
                @Html.ValidationMessageFor(m => m.Title)
            </div>

            <div class="editor-label">
                @Html.LabelFor(m => m.Category)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(m => m.Category)
                @Html.ValidationMessageFor(m => m.Category)
            </div>

            <div class="editor-label">
                @Html.LabelFor(m => m.NewsContent)
            </div>
            <div class="editor-field">
                @Html.TextAreaFor(m => m.NewsContent)
                @Html.ValidationMessageFor(m => m.NewsContent)
            </div>

            <div class="editor-label">
                @Html.Label("SelectedCatgoryId")
            </div>
            <div class="editor-field">
                @Html.DropDownList("SelectedCatgoryId", (IEnumerable<SelectListItem>)ViewBag.Categories)
                @Html.ValidationMessage("SelectedCatgoryId")
            </div>

            <p>
                <input type="submit" value="Log On" />
            </p>
        </fieldset>
    </div>
}

关于c# - Razor 呈现新闻和类别，多种模型，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/9886991/