Folder.Bind抛出ArgumentNullException

Question

我正在尝试创建一个电子邮件客户端，可以使用EWS托管API向我提供特定日期的电子邮件列表，但在调用Folder.Bind（）时我不断收到异常。

  

抛出异常：mscorlib.dll中的'System.ArgumentNullException'   附加信息：值不能为空。

它说它是一个ArgumentNullException，但是一个参数是一个枚举，另一个参数在运行时不是null。从堆栈中看起来似乎是EWS API中的一个例外，它没有很好地处理，但我不知道问题是什么。

这是我的代码。

using Microsoft.Exchange.WebServices.Data;
using System;
using System.Collections.Generic;
using System.Linq;

namespace Integration
{
    public class ExchangeEmailClient : EmailClientBase
    {
        public ExchangeEmailClient(string emailAddress, string password)
        {
            ExchangeService = new ExchangeService();
            ExchangeService.Credentials = new WebCredentials(emailAddress, password);
            ExchangeService.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");
        }

        public ExchangeService ExchangeService { get; private set; }

        public override IEnumerable<Email> Receive(DateTime getFrom)
        {
            //Get emails
            var inbox = Folder.Bind(ExchangeService, WellKnownFolderName.Inbox); //Exception thrown here!
            var filter = new SearchFilter.SearchFilterCollection(LogicalOperator.And, new SearchFilter.IsGreaterThan(ItemSchema.DateTimeReceived, getFrom));
            var emails = inbox.FindItems(filter, new ItemView(int.MaxValue));

            //Transform (use data transformation tool?)
            foreach (EmailMessage exchangeEmail in emails)
            {
                var standardEmail = new Email();
                standardEmail.Body = exchangeEmail.Body;
                standardEmail.Subject = exchangeEmail.Subject;
                standardEmail.From = exchangeEmail.From.Address;

                standardEmail.Attachments = exchangeEmail.Attachments.Select(x => new Uri(x.ContentLocation)).ToList();
                standardEmail.CarbonCopy = exchangeEmail.CcRecipients.Select(x => x.Address).ToList();

                yield return standardEmail;
            }
        }

        public override void Send(Email email)
        {
            var outgoingMail = new EmailMessage(ExchangeService);
            outgoingMail.Body = email.Body;
            outgoingMail.Subject = email.Subject;
            outgoingMail.From = new EmailAddress(email.From);

            //Get attachments
            email.Attachments.ForEach(x => outgoingMail.Attachments.AddFileAttachment(x.ToString()));

            //Set addresses
            email.To.ForEach(x => outgoingMail.ToRecipients.Add(new EmailAddress(x)));
            email.CarbonCopy.ForEach(x => outgoingMail.CcRecipients.Add(new EmailAddress(x)));
            email.BlindCarbonCopy.ForEach(x => outgoingMail.BccRecipients.Add(new EmailAddress(x)));

            //Send
            outgoingMail.SendAndSaveCopy();
        }
    }
}

获取这样的项目会引发相同的异常：

//Get emails 
var filter = new SearchFilter.SearchFilterCollection(LogicalOperator.And, new SearchFilter.IsGreaterThan(ItemSchema.DateTimeReceived, getFrom)); 
var emails = ExchangeService.FindItems(WellKnownFolderName.Inbox, filter, new ItemView(int.MaxValue)); 

在EWS API SDK的2.2.0版和1.2.0版中都会发生这种情况。

Answer 1

此异常在EWS库中处理，我刚关闭了Enable Just My Code。代码执行并正常继续。

资料来源：mr_frostfire @ https://social.msdn.microsoft.com/Forums/en-US/f0806f0b-758c-429d-ad0c-e08274c1660b/getting-impossible-argumentnullexception-from-ensurestrongcryptosettingsinitialized-in?forum=netfxbcl