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c# - System.ArgumentNullException：'值不能为空参数名称：源'

问题描述

我有一个程序连接到一个站点并使用soap api获取订单列表。但我有一个非常奇怪的问题。当 ai 尝试获取没有订单的一天的订单，然后尝试获取一天的订单列表时，我收到此错误。但奇怪的是，如果在出现错误的行中放置一个断点并逐步评估程序，我不会收到任何错误。怎么会这样。这是代码。

https://api.n11.com/ws/OrderService.wsdl

using n11.Deneme.Forms.com.n11.api;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace n11.Deneme.Forms
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string strStartDate = "18/01/2020";
            string strEndDate = "18/01/2020";

            long totalCountValue = 50;
            int currentPageValue = 0;
            int pageCountValue = 1;
            int pageSizeValue = 50;

            Authentication auth = new Authentication();
            auth.appKey = "b891a6b9-cb97-4a7e-9ffb-f7b1e2a593e8";
            auth.appSecret = "pHCjYYadxwTG64Ej";

            OrderSearchPeriod orderSearchPeriod = new OrderSearchPeriod();
            orderSearchPeriod.startDate = strStartDate;
            orderSearchPeriod.endDate = strEndDate;

            OrderDataListRequest orderDataListRequest = new OrderDataListRequest();
            //orderDataListRequest.status = "1";
            orderDataListRequest.period = orderSearchPeriod;
            //orderDataListRequest.orderNumber = "209524598478";

            PagingData pagingData = new PagingData();
            pagingData.currentPage = currentPageValue;
            pagingData.pageCount = pageCountValue;
            pagingData.pageSize = pageSizeValue;
            pagingData.totalCount = totalCountValue;

            DetailedOrderListRequest request = new DetailedOrderListRequest();
            request.auth = auth;
            request.pagingData = pagingData;
            request.searchData = orderDataListRequest;

            OrderServicePortService port = new OrderServicePortService();
            DetailedOrderListResponse response = port.DetailedOrderList(request);
            List<DetailedOrderData> orderList = response.orderList.ToList();

            foreach (var order in orderList)
            {
                MessageBox.Show(order.totalAmount.ToString() + " - " + order.orderNumber + " - " + order.citizenshipId + " - " + order.createDate);

                long orderIdValue = order.id;

                OrderDataRequest orderDataRequest = new OrderDataRequest();
                orderDataRequest.id = orderIdValue;

                OrderDetailRequest orderdetailrequest = new OrderDetailRequest();
                orderdetailrequest.auth = auth;
                orderdetailrequest.orderRequest = orderDataRequest;


                OrderServicePortService port1 = new OrderServicePortService();
                OrderDetailResponse orderDetailResponse = port1.OrderDetail(orderdetailrequest);
                OrderDetailData orderDetail = orderDetailResponse.orderDetail;

                MessageBox.Show(orderDetail.orderNumber);

                List<OrderSearchData> orderItemList = orderDetail.itemList.ToList();

                foreach (var item in orderItemList)
                {

                    MessageBox.Show(item.shipmentInfo.campaignNumber);

                }


            }

        }



    }
}

标签： c#exception

解决方案

如果您在线上遇到错误：

List<DetailedOrderData> orderList = response.orderList.ToList();   //I GOT THE ERROR ON THIS LINE

那么要做的就是看看如何response.orderList获​​取一个值。特别是，它是否对线程、任务、计时器、外部事件或其他类似的东西做某事——这可能意味着它在从 初始返回后不久DetailedOrderList被填充，这可以解释为什么它在您调试和单步执行时起作用（给事情增加一个关键的延迟）。

你也可以简单地做：

var tmp = response.orderList;
if (tmp == null) throw new InvalidOperationException(
    "hey, response.orderList was null! this is not good!");
List<DetailedOrderData> orderList = tmp.ToList();
return orderList;

这将非常清楚和明确地表明这是正在发生的事情。如果你没有得到这个异常，而是别的，那么：需要更多的调试！

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