在MVC视图中的Foreach

假设你的控制器的动作方法是这样的:

public ActionResult AllCategories(int id = 0)
{
    return View(db.Categories.Include(p => p.Products).ToList());
}

将你的模型修改如下:

public class Product
{
    [Key]
    public int ID { get; set; }
    public int CategoryID { get; set; }
    //new code
    public virtual Category Category { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public string Path { get; set; }
    //remove code below
    //public virtual ICollection<Category> Categories { get; set; }
}
public class Category
{
    [Key]
    public int CategoryID { get; set; }
    public string Name { get; set; }
    //new code
    public virtual ICollection<Product> Products{ get; set; }
}

然后你的since now控制器接受一个类别作为模型(而不是产品):

foreach (var category in Model)
{
    <h3><u>@category.Name</u></h3>
    <div>
        <ul>    
            @foreach (var product in Model.Products)
            {
                // cut for brevity, need to add back more code from original
                <li>@product.Title</li>
            }
        </ul>
    </div>
}

更新:添加ToList()到控制器返回语句

你有:

foreach (var category in Model.Categories)

然后

@foreach (var product in Model)

根据该视图和模型，Model似乎属于Product类型，如果是，则第二个foreach无效。实际上，如果您返回Product的集合，第一个可能是无效的。

更新:

你是对的，我要退回产品类型的型号。我也是既然你已经指出了问题所在，你就应该明白是哪里出了问题。我怎么样?如果我不能这样做我就该做我想做的事

当你说你返回一个Product类型的模型时，我很惊讶你的代码编译。你可以这样做:

@foreach (var category in Model)
{
    <h3><u>@category.Name</u></h3>
    <div>
        <ul>    
            @foreach (var product in category.Products)
            {
                <li>
                    put the rest of your code
                </li>
            }
        </ul>
    </div>
}

这表明，而不是返回Product，您返回Category 与Products的集合。类似于EF:

// I am typing it here directly 
// so I'm not sure if this is the correct syntax.
// I assume you know how to do this,
// anyway this should give you an idea.
context.Categories.Include(o=>o.Product)

试试这个:

看起来每次都是针对每个产品进行循环，现在这里是针对与当前循环的类别ID相同的每个产品进行循环

<div id="accordion1" style="text-align:justify">
@using (Html.BeginForm())
{
    foreach (var category in Model.Categories)
    {
        <h3><u>@category.Name</u></h3>
        <div>
            <ul>    
                @foreach (var product in Model.Product.Where(m=> m.CategoryID= category.CategoryID)
                {
                    <li>
                        @product.Title
                        @if (System.Web.Security.UrlAuthorizationModule.CheckUrlAccessForPrincipal("/admin", User, "GET"))
                        {
                            @Html.Raw(" - ")  
                            @Html.ActionLink("Edit", "Edit", new { id = product.ID })
                        }
                        <ul>
                            <li>
                                @product.Description
                            </li>
                        </ul>
                    </li>
                }
            </ul>
        </div>
    }
}  

控制器

public ActionResult Index()
    {

        //you don't need to include the category bc it does it by itself
        //var model = db.Product.Include(c => c.Category).ToList()
        ViewBag.Categories = db.Category.OrderBy(c => c.Name).ToList();
        var model = db.Product.ToList()
        return View(model);
    }

视图

您需要使用给定的类别

like:=> Model.where(p=>p。CategoryID == CategoryID)

试试这个…

@foreach (var category in ViewBag.Categories)
{
    <h3><u>@category.Name</u></h3>
    <div>
        @foreach (var product in Model.where(p=>p.CategoryID == category.CategoryID))
        {
                <table cellpadding="5" cellspacing"5" style="border:1px solid black; width:100%;background-color:White;">
                    <thead>
                        <tr>
                            <th style="background-color:black; color:white;">
                                @product.Title  
                                @if (System.Web.Security.UrlAuthorizationModule.CheckUrlAccessForPrincipal("/admin", User, "GET"))
                                {
                                    @Html.Raw(" - ")  
                                    @Html.ActionLink("Edit", "Edit", new { id = product.ID }, new { style = "background-color:black; color:white !important;" })
                                }
                            </th>
                        </tr>
                    </thead>
                    <tbody>
                        <tr>
                            <td style="background-color:White;">
                                @product.Description
                            </td>
                        </tr>
                    </tbody>      
                </table>                       
            }

    </div>
}