c#如何通过ews 获取exchange里的收件箱全部邮件而非未读邮件？

[netboygg]

现在从网上找的代码无论如何都得不到收件箱里的全部邮件，只能取到未读邮件，不知道为什么。求解决方案哈：
一下是代码：

ServicePointManager.ServerCertificateValidationCallback = CertificateValidationCallBack;
                ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010_SP2);//如果是Exchange 2010，则切换到2010
                ICredentials creds = new NetworkCredential("xxxx", "xxxx", "xxxx.com");
                service.Credentials = new WebCredentials(creds);
                service.Url = new Uri("https://xxxxxx/xxx/Exchange.asmx");
                service.PreAuthenticate = true;
                service.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, userMailAddress);
                ItemView view = new ItemView(int.MaxValue);
                FindItemsResults<Item> findResults = service.FindItems(WellKnownFolderName.Inbox, SetFilter(), view);

                foreach (Item item in findResults.Items)
                {
                    if (item.Subject != null)
                    {
                        list.Add(item.Subject.ToString());
                    }
                    else
                    {
                        list.Add("无标题");
                    }
                    list.Add(item.DateTimeSent.ToString());
                }

private SearchFilter SetFilter()
        {
            List<SearchFilter> searchFilterCollection = new List<SearchFilter>();
            searchFilterCollection.Add(new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead, false));//这里的.IsRead，false或者true都是去到未读邮件，不知道为什么
            SearchFilter s = new SearchFilter.SearchFilterCollection(LogicalOperator.And, searchFilterCollection.ToArray());
            return s;
        }

[Tomzhout]

//SetFilter方法改成这样就可以了。 private static SearchFilter SetFilter() { List<SearchFilter> searchFilterCollection = new List<SearchFilter>(); searchFilterCollection.Add(new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead, false)); searchFilterCollection.Add(new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead, true)); SearchFilter s = new SearchFilter.SearchFilterCollection(LogicalOperator.Or, searchFilterCollection.ToArray()); return s; }