導覽屬性Navigate property之研究

 

• Product VS ProductCategory 為1對1

 

• //以下指令會新增Product與ProductCategory

db.Products.Add(new Product() { Name = "文具" + "類別下的商品1", Color = Color.Red, Description = "N/A", Price = 99, PublishOn = DateTime.Now, 

ProductCategory = new ProductCategory() { Id = 1, Name = "文具" } });

 

• 如果Product裡的ProductCategory屬性不新增的話，應該可以變成只新增Product

A：是不行的，因為Product對ProductCategory是一對一關係，

所以當實現Prouduct時也必須實現ProuductCategory；

反之ProductCategory對Prouduct是ㄧ對多關係，

實現ProuductCategory時Prouduct可為Null。

另外OrderHeader對OrderDetail也是ㄧ對多關係。

 

• 新增類別以下導覽屬性有Key就不新增，沒有對應的Key就新增一筆

 

using eComerce.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Drawing;

namespace eComerce.Controllers
{
    //[Authorize] // 必須登入會員才能使用訂單結帳功能
    public class OrderController : BaseController
    {
        // 顯示完成訂單的表單頁面
        public ActionResult Complete()
        {
            return View();
        }
    // 將訂單資料與購物車資料寫入資料庫
    [HttpPost]
    public ActionResult Complete(OrderHeader form)
    {
        MyDbContext db = new MyDbContext();

        //db.ProductCategories.Add(new ProductCategory() { Id = 1, Name = "文具" });
        //db.SaveChanges();

        //以下指令會新增Product與ProductCategory
        db.Products.Add(new Product() { Id = 1, Name = "文具" + "類別下的商品1", Color = Color.Red, Description = "N/A", Price = 99, PublishOn = DateTime.Now, ProductCategory = new ProductCategory() { Id = 1, Name = "文具" } });
        db.SaveChanges();

        //手動建立購物車測試資料
        Product Product2 = new Product() { Id = 2, Name = "文具" + "類別下的商品1", Color = Color.Red, Description = "N/A", Price = 99, PublishOn = DateTime.Now, ProductCategory = new ProductCategory() { Id = 2, Name = "文具" } };
        Cart Cart = new Cart() { Product = Product2, Amount = 123 };
        this.Carts.Add(Cart);

        // 將訂單資料與購物車資料寫入資料庫
        OrderHeader oh = new OrderHeader()
        {
            //Member = member,
            ContactName = form.ContactName,
            ContactAddress = form.ContactAddress,
            ContactPhoneNo = form.ContactPhoneNo,
            BuyOn = DateTime.Now,
            Memo = form.Memo,
            OrderDetailItems = new List<orderdetail>()
        };

        int total_price = 0;
        foreach (var item in this.Carts)
        {
            total_price += item.Product.Price * item.Amount;
            oh.OrderDetailItems.Add(new OrderDetail() { Product = Product2, Price = Product2.Price, Amount = item.Amount });
        }

        oh.TotalPrice = total_price;

        db.Orders.Add(oh);
        db.SaveChanges();

        // 訂單完成後必須清空現有購物車資料
        this.Carts.Clear();

        // 訂單完成後回到網站首頁
        return RedirectToAction(&quot;Complete&quot;, &quot;Order&quot;);
    }
}

}