• 建立 ShoppingCartVM View_Model
  • 用於合併購物車的金額與訂單

public class ShoppingCartVM
    {
     public IEnumerable<ShoppingCart> ShoppingCartList { get; set; }
      public OrderHeader OrderHeader { get; set; }
    }

• Customer新增Controller與View。
  • 新建=>控制器=>空白=>CartController
  • 對Index右鍵=>新增View
• _Layout增加購物車按鈕

@model ClothShop.Models.ViewModels.ShoppingCartVM
<form method="post">
    <br />
    <div class="container">
        <div class="card">
            <div class="card-header bg-primary text-light ml-0">
                <div class="row align-items-center">
                    <div class="col-6">
                        <i class="fa fa-shopping-cart"></i>
                        <p class="mb-0">購物車 Shopping Cart</p>
                    </div>
                    <div class="col-6 text-end">
                        <a asp-area="Customer" asp-controller="Home" asp-action="Index" class="btn btn-info btn-sm">繼續購物 Continue Shopping</a>
                    </div>
                </div>
            </div>
            <div class="card-body">
                @foreach (var item in Model.ShoppingCartList)
                {
                    <div class="row">
                        <div class="d-none d-lg-block col-lg-3 text-center py-2">
                            <img src="@item.Product.ImageUrl" class="rounded" width="75%" />
                        </div>
                        <div class="col-12 col-lg-4 pt-md-3">
                            <h5><strong>產品名稱</strong></h5>
                            <p><small>@item.Product.Name</small></p>
                            <h5>顏色 Color</h5>
                            <p><small>@item.Color</small></p>
                            <h5>尺寸 Size</h5>
                            <p><small>@item.Size</small></p>
                        </div>
                        <div class="col-12  col-lg-5 text-center row">
                            <div class="col-4 text-md-right pt-4">
                                <h6><strong>$ @item.Product.Price <span class="text-muted">x</span> @item.Count </strong></h6>
                            </div>
                            <div class="col-6 col-sm-4 col-lg-6 pt-2">
                                <div class="w-75 btn-group" role="group">
                                    <a asp-action="plus" asp-route-cartId="@item.Id" class="btn btn-primary">plus</a> &nbsp;
                                    <a asp-action="minus" asp-route-cartId="@item.Id" class="btn btn-warning">minus</a>
                                </div>
                            </div>
                            <div class="col-2 col-sm-4 col-lg-2 text-right pt-2">
                                <a asp-action="remove" asp-route-cartId="@item.Id" class="btn btn-danger">
                                    <i class="bi bi-trash-fill"></i>
                                </a>
                            </div>
                        </div>
                    </div>
                    <hr />
                }
            </div>
            <div class="row">
                <div class="col-12 col-md-6 offset-md-6 col-lg-4 offset-lg-8 pr-4">
                    <ul class="list-group">
                        <li class="list-group-item d-flex justify-content-between bg-light">
                            <span class="text-info"> 總金額 (NT)</span>
                            <strong class="text-info">@Model.OrderHeader.OrderTotal.ToString("c")</strong>
                        </li>
                    </ul>
                </div>
            </div>

            <div class="card-footer">
                <div class="card-footer row justify-content-end">
                    <div class="col-sm-12 col-lg-4 col-md-6 pe-0">
                        <a asp-action="Summary" class="btn btn-success form-control">總計 Summary</a>
                    </div>
                </div>
            </div>
        </div>
    </div>
</form>

• CartController設置
  • IUnitOfWork下方設定購買商品時，自動綁定ShoppingVM

 [Area("Customer")]
    [Authorize]
    public class CartController : Controller
    {
private readonly IUnitOfWork _unitOfWork;
[BindProperty]
public ShoppingCartVM ShoppingCartVM { get; set; }
public CartController(IUnitOfWork unitOfWork)
{
    _unitOfWork = unitOfWork;
}
 public IActionResult Index()
        {
            var claimsIdentity = (ClaimsIdentity)User.Identity;
            var userId = claimsIdentity.FindFirst(ClaimTypes.NameIdentifier).Value;
            ShoppingCartVM = new()
            {
                ShoppingCartList = _unitOfWork.ShoppingCart.GetAll(u => u.ApplicationUserId == userId, includeProperties: "Product"),
                OrderHeader = new()
            };
            foreach (var cart in ShoppingCartVM.ShoppingCartList)
            {
                ShoppingCartVM.OrderHeader.OrderTotal += (cart.Product.Price * cart.Count);
            }
            return View(ShoppingCartVM);
        }
}

• ShoppingCart數量修改

 public IActionResult Plus(int cartId)
{
    var cartFromDb = _unitOfWork.ShoppingCart.Get(u => u.Id == cartId);
    cartFromDb.Count += 1;
    _unitOfWork.ShoppingCart.Update(cartFromDb);
    _unitOfWork.Save();
    return RedirectToAction(nameof(Index));
}

 public IActionResult Minus(int cartId)
{
    var cartFromDb = _unitOfWork.ShoppingCart.Get(u => u.Id == cartId);
    if (cartFromDb.Count <= 1)
    {
_unitOfWork.ShoppingCart.Remove(cartFromDb);
    }
    else
    {
cartFromDb.Count -= 1;
_unitOfWork.ShoppingCart.Update(cartFromDb);
    }
    _unitOfWork.Save();
    return RedirectToAction(nameof(Index));
}

 public IActionResult Remove(int cartId)
{
    var cartFromDb = _unitOfWork.ShoppingCart.Get(u => u.Id == cartId);
    _unitOfWork.ShoppingCart.Remove(cartFromDb);
    _unitOfWork.Save();
    return RedirectToAction(nameof(Index));
}