使用HttpContext.Session.Get/Set报错：ISession无对应定义求助

问题场景 #

构建简单电商系统时，需要将选中的商品列表存入订单报表，在使用HttpContext.Session.Get<List<Product>>和Set方法时，出现错误提示：ISession doesn't contain a definition for 'Get'，Set方法也报相同错误。已引入Microsoft.AspNetCore.Http.Extensions、Microsoft.AspNetCore.Http、Microsoft.Extensions.Configuration命名空间，但问题仍未解决。

控制器代码 #

namespace EshopTest5.Controllers
{
    public class OrderController : Controller
    {
        private readonly ApplicationDbContext _context;
        private readonly IHttpContextAccessor _httpcontext;

        public OrderController(ApplicationDbContext context, IHttpContextAccessor httpcontext)
        {
            _context = context;
            _httpcontext = httpcontext;
        }

        // GET: OrderController/Checkout
        public IActionResult Checkout()
        {
            return View();
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Checkout(Order anOrder)
        {
            List<Product> products =_httpcontext.HttpContext.Session.Get<List<Product>>("products");
            if (products != null)
            {
                foreach (var product in products)
                {
                    OrderDetails orderDetails = new OrderDetails();
                    orderDetails.PorductId = product.ProductId;
                    anOrder.OrderDetails.Add(orderDetails);
                }
            }

            anOrder.OrderNo = GetOrderNo();
            _context.Orders.Add(anOrder);
            await _context.SaveChangesAsync();
            HttpContext.Session.Set("products", new List<Product>());
            return View();
        }
    }
}

Program.cs代码 #

using EshopTest5.Data;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer(connectionString));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();

builder.Services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<ApplicationDbContext>();

builder.Services.AddControllersWithViews();

builder.Services.AddHttpContextAccessor();

builder.Services.AddSession();
var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseMigrationsEndPoint();
}
else
{
    app.UseExceptionHandler("/Home/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();
app.UseSession();

app.UseAuthentication();
app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");
app.MapRazorPages();

app.Run();

解决方案 #

1. 安装必要的NuGet包 #

ISession的泛型Get<T>和Set<T>扩展方法并非ASP.NET Core框架核心自带，需要安装Microsoft.AspNetCore.Session NuGet包：

• 使用Package Manager控制台：

  Install-Package Microsoft.AspNetCore.Session
  

• 或者通过Visual Studio的NuGet包管理器搜索并安装该包。

2. 手动实现Session扩展方法（可选） #

如果不想额外安装包，可以自己实现序列化/反序列化的扩展方法，使用System.Text.Json处理对象转换：

using Microsoft.AspNetCore.Http;
using System.Text.Json;

public static class SessionExtensions
{
    public static void Set<T>(this ISession session, string key, T value)
    {
        session.SetString(key, JsonSerializer.Serialize(value));
    }

    public static T Get<T>(this ISession session, string key)
    {
        var value = session.GetString(key);
        return value == null ? default : JsonSerializer.Deserialize<T>(value);
    }
}

将这个类放在项目的合适目录（比如Extensions文件夹），然后在控制器中引入对应的命名空间即可使用。

3. 修正代码中的拼写错误 #

注意到控制器代码中orderDetails.PorductId存在拼写错误，应改为orderDetails.ProductId，避免后续订单详情关联商品时出现数据错误。

内容的提问来源于stack exchange，提问作者ha33