使用 ViewModel 读取与实体框架 6 的多列表相关数据

Question

我想在我的MVC 5 MarketPlace项目中使用EF 6。我的数据库中有许多相关的行。当我使用上下文模型时，一切都很好，但我无法使用视图模型来访问相关数据。我是新手，所以我阅读了有关相关数据的懒惰、急切和显式加载的信息。当代码调用带有 ID 的控制器时，目标行和关联也会响应，但我想列出我所有的类别行以及它们在 Home 索引中的相关行，所以如果可能的话，我需要一些提示。

型

    public partial class Category : Repository.Pattern.Ef6.Entity
{
    public Category()
    {
        this.CategoryPictures = new List<CategoryPicture>();
        this.CategoryListingTypes = new List<CategoryListingType>();
        this.CategoryStats = new List<CategoryStat>();
        this.Listings = new List<Listing>();
        this.MetaCategories = new List<MetaCategory>();
    }
    public int ID { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public int Parent { get; set; }
    public bool Enabled { get; set; }
    public int Ordering { get; set; }
    public virtual ICollection<CategoryListingType> CategoryListingTypes { get; set; }
    public virtual ICollection<CategoryStat> CategoryStats { get; set; }
    public virtual ICollection<Listing> Listings { get; set; }
    public virtual ICollection<CategoryPicture> CategoryPictures { get; set; }
    public virtual ICollection<MetaCategory> MetaCategories { get; set; }
}

视图模型

    public class CategoryItemModel
{
    public List<ListingItemModel> CategoryListings { get; set; }
    public List<Category> CategoryOthers { get; set; }
    public Category CategoryCurrent { get; set; }
    public string UrlPicture { get; set; }
    public List<CategoryPictureModel> Pictures { get; set; }
}

类别详细信息控制器

 public virtual async Task<ActionResult> Category(int id)
    {
        var itemQuery = await _categoryService.Query(x => x.ID == id)
            .Include(x => x.CategoryPictures)
            .Include(x => x.CategoryListingTypes)
            .Include(x => x.Listings)
            .Include(x => x.CategoryStats)
            .SelectAsync();
        var item = itemQuery.FirstOrDefault();
        if (item == null)
            return new HttpNotFoundResult();
        var itemsList = _listingService.Queryable()
            .Where(x => x.CategoryID == id
                && (x.Enabled != false || x.Active != false)
                && (x.EndDate >= DateTime.Now || x.StartDate <= DateTime.Now))
                .ToList();
        var itemsModel = new List<ListingItemModel>();
        foreach (var list in itemsList.OrderByDescending(x => x.Created))
        {
            itemsModel.Add(new ListingItemModel()
            {
                ListingCurrent = list,
                UrlPicture = list.ListingPictures.Count == 0 ? ImageHelper.GetListingImagePath(0) : ImageHelper.GetListingImagePath(list.ListingPictures.OrderBy(x => x.Ordering).FirstOrDefault().PictureID)
            });
        }

        var pictures = await _categoryPictureservice.Query(x => x.CategoryID == id).SelectAsync();
        var picturesModel = pictures.Select(x =>
            new CategoryPictureModel()
            {
                ID = x.PictureID,
                Url = ImageHelper.GetCategoryImagePath(x.PictureID),
                CategoryID = x.CategoryID,
                Ordering = x.Ordering
            }).OrderBy(x => x.Ordering).ToList();
        var itemModel = new CategoryItemModel()
        {
            CategoryCurrent = item,
            CategoryListings = itemsModel,
            Pictures = picturesModel
        };
        return View("~/Views/Listing/Category.cshtml", itemModel);
    }

请我列出我的所有类别及其相关数据(图片，列表，统计数据(。非常感谢您的任何提示。

Answer 1

我想要列出我的所有类别及其相关数据(图片，列表，统计信息(

然后对查询运行 ToList：

    var  categories = await _categoryService.Query(x => x.ID == id)
        .Include(x => x.CategoryPictures)
        .Include(x => x.CategoryListingTypes)
        .Include(x => x.Listings)
        .Include(x => x.CategoryStats)
        .ToList();

Answer 2

 public virtual async Task<ActionResult> Categories()
    {
        var items = await _categoryService.GetAll()
            .Include(x => x.CategoryPictures)
            .Include(x => x.CategoryListingTypes)
            .Include(x => x.Listings)
            .Include(x => x.CategoryStats)
            .ToListAsync();

        return View(items);
    }