Question

我有2个为以下对象创建视图模型的类：

ELSE 0

ViewModel：

NULL

我正在尝试显示所有糖果的列表，包括当前购物车中每种糖果的数量（该糖果在当前购物车中可能不存在）。

我已经编写了所需数据的基本查询，但是不确定如何以MVC方式执行此操作：

ELSE

控制器：

SUM()

查看：

public class Sweet
{
    public int SweetID { get; set; }

    public int CategoryID { get; set; }
    public Category Category { get; set; }
    public string SweetName { get; set; }
    public bool Singular { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }


    public virtual ICollection<Cart> Carts { get; set; }
}


public class Cart
{
    [Key]
    public int RecordID { get; set; }
    public string CartID { get; set; }
    public int SweetID { get; set; }
    public int PemixID { get; set; }
    public int Qty { get; set; }
    public System.DateTime DateCreated { get; set; }

    public Sweet Sweet { get; set; }
    public PreMix PreMix { get; set; }

}

Answer 1

通过查看视图，您想显示“ SweetName”和“ Qty”。

因此，您必须像这样重构“ SweetViewModel”

public class SweetViewModel
    {
        //From Sweet Model
        public int SweetID { get; set; }
        public int CategoryID { get; set; }
        public Category Category { get; set; }
        public string SweetName { get; set; }
        public bool Singular { get; set; }
        public string Description { get; set; }
        public decimal Price { get; set; }

        //From Cart Model
        public int Qty { get; set; }
    }

根据您的输出，您必须像这样设计视图

@model IEnumerable<WebApplication1.ViewModels.SweetViewModel>

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>SweetTestArea</title>
</head>
<body>
    <p>
        @Html.ActionLink("Create New", "Create")
    </p>
    <table class="table">    
    @foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.SweetID)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.CategoryID)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.SweetName)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Description)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Price)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Qty)
            </td>
        </tr>
    }

    </table>
</body>
</html>

您的控制器代码将类似于

 public ActionResult SweetTestArea()
        {
            List<SweetViewModel> viewModel = new List<SweetViewModel>();

            var q = (from s in db.Sweets
                     join c in db.Carts on s.SweetID equals c.SweetID
                     where c.CartID == "7125794e-38f4- 4ec3-b016-cd8393346669"
                     select new SweetViewModel
                     {
                         CategoryID = s.CategoryID,
                         Description = s.Description,
                         Price = s.Price,
                         Qty = c.Qty,
                         SweetID = s.SweetID,
                         SweetName = s.SweetName
                     });

            viewModel = q.ToList();

            return View(viewModel);
        }

如果您想退出联接，则您的linq查询将为

var q = (from s in db.Sweets
                     join c in db.Carts on s.SweetID equals c.SweetID into j
                     from c in j.DefaultIfEmpty()
                     where c.CartID == "7125794e-38f4- 4ec3-b016-cd8393346669"
                     select new SweetViewModel
                     {
                         CategoryID = s.CategoryID,
                         Description = s.Description,
                         Price = s.Price,
                         Qty = c.Qty,
                         SweetID = s.SweetID,
                         SweetName = s.SweetName
                     });

我建议您不要使用左联接，因为您希望从Sweet和Cart的两个模型中都在购物车中显示数据，这意味着购物车中有至少1个数量的商品。

编辑：

根据我对您的最后一条评论的理解，您希望每件商品都显示在购物车中，无论是否显示在购物车模型中

为此

1）让我们先拿购物车中的物品

List<SweetViewModel> cart = new List<SweetViewModel>();

            var q = (from s in db.Sweets
                     join c in db.Carts on s.SweetID equals c.SweetID into l
                     from c in l.DefaultIfEmpty()
                     where c.CartID == "7125794e-38f4- 4ec3-b016-cd8393346669"
                     select new SweetViewModel
                     {
                         CategoryID = s.CategoryID,
                         Description = s.Description,
                         Price = s.Price,
                         Qty = c.Qty,
                         SweetID = s.SweetID,
                         SweetName = s.SweetName
                     });


            cart = q.ToList();

2）然后获取所有糖果并将其投影到SweetViewModel

List<SweetViewModel> allSweets = new List<SweetViewModel>();

            var w = (from s in db.Sweets
                     select new SweetViewModel
                     {
                         CategoryID = s.CategoryID,
                         Description = s.Description,
                         Price = s.Price,
                         Qty = 0,
                         SweetID = s.SweetID,
                         SweetName = s.SweetName
                     });

            allSweets = w.ToList();

3）过滤掉购物车中存在的那些糖果您将在下面的过滤列表中得到甜蜜的ID

var filteredSweets = allSweets.Select(x => x.SweetID).Where(x => !cart.Select(y => y.SweetID).Contains(x)).ToList();

4）将经过过滤的糖果添加到模型中

List<SweetViewModel> viewModel = new List<SweetViewModel>();

            foreach (var i in filteredSweets)
                viewModel.Add(allSweets.Where(x => x.SweetID == i).Take(1).SingleOrDefault());

5）然后将您的购物车商品添加到视图模型中

viewModel.AddRange(cart);

并将此视图模型返回视图。

您可以根据需要使用order by对购物车中的物品进行排序。

是否有可能在显示的模型/ viewmodel上包含一个不包含导航属性的模型

1 个答案: