添加Microsoft.ServiceModel.Channels.Mail.dll 

Microsoft.ServiceModel.Channels.Mail.ExchangeWebService.dll

public class ExchangeMailManage
    {
        public static List<EmailItem> GetMailMessageFilter(string userName, string passWord, string domain, string url, string houzhui, string filterString)
        {
            List<EmailItem> lst = new List<EmailItem>();
            try
            {
                //ExchangeService版本为2007SP1  
                ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
                //参数是用户名,密码,域  
                service.Credentials = new WebCredentials(userName, passWord, domain);
                //给出Exchange Server的URL 
                service.Url = new Uri(url);
                //你自己的邮件地址 xxx@xxx.xxx  
                service.AutodiscoverUrl(userName + "@" + houzhui);
                //创建过滤器, 条件为邮件未读.  
                if (String.IsNullOrEmpty(filterString))
                {
                    filterString =" ";
                }
                SearchFilter sf = new SearchFilter.ContainsSubstring(EmailMessageSchema.Subject, filterString);
                //SearchFilter sf = new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead,false);
                //查找Inbox,加入过滤器条件,结果queryCount条
                FindItemsResults<Item> findResults = service.FindItems(
                    WellKnownFolderName.Inbox,
                    sf,
                    new ItemView(CommonStatic.MaxUnReadEmailCount));
                //new SearchFilter.IsGreaterThanOrEqualTo(EmailMessageSchema.Subject
                foreach (Item item in findResults.Items)
                {
                    EmailMessage email = EmailMessage.Bind(service, item.Id);
                    if (email.IsRead && !TxtFileManage.IsContainTxt(item.Id.UniqueId))
                    {
                        EmailItem emailItem = new EmailItem();
                        emailItem.ID = item.Id.UniqueId;
                        emailItem.Subject = email.Subject;
                        emailItem.Content = email.Body.Text;
                        lst.Add(emailItem);
                        //标记为已读  
                        //email.IsRead = true;
                        //将对邮件的改动提交到服务器  
                        //email.Update(ConflictResolutionMode.AlwaysOverwrite);
                    }
                }               
            }
            catch (Exception ex)
            {
                LogWriter.LogErrorEvent("Nagios", ex.Message);
            }
            return lst;
        }
    }