Question

我正在尝试为具有特定订单的特定客户输出付款计划。

我不断收到此错误：

 info:Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor[1]
  Executing ObjectResult, writing value of type 'null'.

我做错了什么，但不确定是什么。寻找解决方案很长时间没有运气。我是编程和C＃的新手，所以仍然想摆脱这个问题。非常感谢您的帮助和指导。

这是我到目前为止所拥有的：

型号：

using System.Collections.Generic;

namespace Project.Models
{
    public class Customer
    {
       public string CustomerId { get; set; }
       public string FirstName { get; set; }
       public string LastName { get; set; }
       public string DateOfBirth { get; set; }
    }

   public class Order
   {
       public string OrderId { get; set; }
       public string Product { get; set; }
       public string Status { get; set; }
       public double Price { get; set; }
   }

    public class CustomerOrder
    {
      public string CustomerId {get; set;}
      public string OrderId { get; set; }
    } 

    public class Repayment
    {
      public int Amount { get; set; }
      public string DueDate { get; set; }
      public string RepaymentId { get; set; }
    }

   public class Choice
   {
      public string ChoiceId { get; set; }
      public List<Repayment> Repayments{ get; set; }
   }

   public class RepaymentPlan
   {
      public List<Choice> Choices{ get; set; }
   }
}

存储库：

using System.Collections.Generic;
using System.Linq;
using Project.Models;
using System.Net;
using System.Collections.Specialized;
using System.Text;


namespace Project.Repositories
{
   public class OrderRepository
   {

       private static List<Order> _Orders;
       private static List<CustomerOrder> _CustomerOrder;
       private static List<RepaymentPlan> _RepaymentPlan;

       static OrderRepository()
       {
           _Orders = new List<Order>();
           _CustomerOrder= new List<CustomerOrder>();
           _PaymentPlan = new List<PaymentPlan>();

           _Orders.Add(new Order
           {
               OrderId = "124",
               Product= "Shirts",
               Status= "On it's way",
               Price= 100.20,
           });

           _Orders.Add(new Order
           {
               OrderId= "122",
               Product= "Pants",
               Status= "Not ready",
               Price= 300.30,
           });

           _Orders.Add(new Order
           {
               OrderId= "143",
               Product= "Deadpool",
               Status= "On it's way",
               Price= 6.20,
           });

           _Orders.Add(new Order
           {
               OrderId= "156",
               Product= "Socks",
               Status= "Not ready",
               Price= 3.30,
           });

           _CustomerOrder.Add(new CustomerOrder
           {
               CustomerId = "578",
               OrderId = "156",
           });

           _RepaymentPlan.Add(new RepaymentPlan 
          {
             choices = new List<Choice>
                        {
                            new Choice
                            {
                                choiceId = "cho1",
                                Repayments = new List<Repayment>
                                                {
                                                    new Repayment
                                                    {
                                                        amount = 200,
                                                        dueDate = "2018-06-01"
                                                    }, 
                                                    new Repayment
                                                    {
                                                        amount = 100,
                                                        dueDate = "2018-08-01",
                                                    }
                                                }
                            }, 
                            new Choice
                            {
                                choiceId = "cho2",
                                repayments = new List<Repayment>
                                                {
                                                    new Repayment
                                                    {
                                                        repaymentId = "Choice1",
                                                        amount = 300,
                                                        dueDate = "2018-10-01"
                                                    }, 
                                                    new Repayment
                                                    {
                                                        repaymentId = "Choice2",
                                                        amount = 150,
                                                        dueDate = "2018-11-01"
                                                    }, 
                                                }
                            }                                             
                        },
             });
}

 public static RepaymentPlan GetRepaymentPlan(string customerId, string orderId)
 {
     var customerlist =_CustomerOrder.FindAll(c => c.CustomerId==customerId); 
     var orderlist= _CustomerOrder.FindAll(c => c.orderId==orderId);
     var pplist= new RepaymentPlan();

     if (customerlist == orderlist)
     {
         return pplist;
     }
     return null;
 }

控制器：

OrderController.cs：

using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Project.Models;
using Project.Repositories;

namespace Project.Controllers
{
   public class OrderController : Controller
   {
      [HttpGet("customers/{customerid}/orders/{orderId}/paymentPlan")]
      public RepaymentPlan FindRepaymentPlan(string customerId, string orderId)
      {   
          return OrderRepository.GetRepaymentPlan(customerId, orderId);
      }
    }
 }

Answer 1

好的，仔细检查代码后，我发现问题出在此方法中

public static RepaymentPlan GetRepaymentPlan(string customerId, string orderId)

您将始终返回null，因为您的情况将始终为false。这适用于任何（可能）编程语言。 if (customerlist == orderlist)评估两个对象是否相同（它们引用相同的内存地址），而不评估这些对象的内容。要查看两个对象是否具有相同的数据，可以使用循环（for，while）。但是，由于您使用了Linq，因此在FindAll函数中使用多个条件就足够了。

public static RepaymentPlan GetRepaymentPlan(string customerId, string orderId)
{
 var customerlist =_CustomerOrder.FindAll(c => c.CustomerId==customerId && c.orderId==orderId); 
 var pplist= new RepaymentPlan();

 if (customerlist.Any())
 {
     return pplist; 
 }
 return null;
}

此外，您可能希望返回customerlist.First()而不是pplist。如果返回类型为RepaymentPlan的空对象，则可能对您没有帮助。

JSON中没有数据输出-获取204错误代码

1 个答案: