ASP.NET 核心 MVC - 有什么方法可以更改带有会话的模型上特定数据的值吗？

Question

有什么方法可以更改模型上特定数据的值吗？例如我的模型包含

item_id item_description 数量

并且您使用会话在数据模型上有很多记录。在更改数量期间输入我想用会话更新模型的值？推荐吗？还是有比我的方法更好的方法？谢谢。

Answer 1

What I was trying to achieve is to modify the data inside the session. Is modifying data on session also working like a database? where you can get the id and modify the data that you want?

根据你的描述，我假设你正在使用 Session 来记录列表，现在你想更新会话数据，对吗？如果是这样的话，你可以参考下面的例子：

参考this article启用Startup.cs文件中的会话中间件

[注意]：请记得通过 IdleTimeout 属性设置会话过期时间。而且，由于您使用会话来存储对象列表，请记住添加 SessionExtensions.

     //required using Microsoft.AspNetCore.Http;
     //required 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);
         }
     }

添加项目视图模型：

 public class ItemViewModel
 {
     public int ItemId { get; set; }
     public string ItemDescription { get; set; }
     public int Quantity { get; set; }
 }

控制器：我正在使用存储库来设置初始数据。从session中获取数据后，我们可以修改数据，然后调用set方法将最新的数据保存到session中。

 private readonly ApplicationDbContext _context;
 private readonly IDataRepository _repository; 
 public TestController(ApplicationDbContext context, IDataRepository repository)
 {
     _context = context;
     _repository = repository; 
 }

 private readonly string SessionKeyName = "itemlist";
 public IActionResult ItemIndex()
 {
     List<ItemViewModel> items = new List<ItemViewModel>();
     //check if the session is exist or not.
     if (HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName) == default)
     {   //get the initial data.
         items = _repository.GetItemViewModels();
         //set value to the session.
         HttpContext.Session.Set<List<ItemViewModel>>(SessionKeyName, items);
     }
     else
     {
         items = HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName);
     } 
     return  View(items);
 }
 public IActionResult EditItem(int Id)
 {
     List<ItemViewModel> items = new List<ItemViewModel>();
     //check if the session is exist or not.
     if (HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName) == default)
     {
         items = _repository.GetItemViewModels();
         //set value to the session.
         HttpContext.Session.Set<List<ItemViewModel>>(SessionKeyName, items);
     }
     else
     {
         items = HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName);
     }

     return View(items.Where(c=>c.ItemId == Id).FirstOrDefault());
 }
 [HttpPost]
 public IActionResult EditItem(ItemViewModel item)
 {
     List<ItemViewModel> items = new List<ItemViewModel>();
     //check if the session is exist or not.
     if (HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName) == default)
     {
         items = _repository.GetItemViewModels();
         //set value to the session.
         HttpContext.Session.Set<List<ItemViewModel>>(SessionKeyName, items);
     }
     else
     {
         items = HttpContext.Session.Get<List<ItemViewModel>>(SessionKeyName);
     }

     //based on the primary key to find the special item,
     var i = items.Where(c => c.ItemId == item.ItemId).FirstOrDefault();
     //update the quantity.
     i.Quantity = item.Quantity;
     //Update the session with the latest data.
     HttpContext.Session.Set<List<ItemViewModel>>(SessionKeyName, items);
     //redirect to the ItemIndex action and reload the Index page.
     return RedirectToAction(nameof(ItemIndex));
 }

结果是这样的：

ASP.NET 核心 MVC - 有什么方法可以更改带有会话的模型上特定数据的值吗？

ASP.NET Core MVC - Is there any way to change the value of specific data on model with session?

model-view-controller

asp.net-core