MVC3-实体对象不能被ientitychangetracker的多个实例引用

我经历了类似的问题，但它能解决我的目的。我在两个方面使用相同的代码：1。直接通过按钮按下2。通过计划任务。

通过方法1，它工作良好，但方法2给出了该误差。我的代码：

服务-

public virtual int SendCampaign(Campaign campaign, EmailAccount emailAccount,
        IEnumerable<NewsLetterSubscription> subscriptions)
    {
        var campaignSubscriberTrack = new CampaignNewsletterSubscriberTrack();  
        if (campaign == null)
            throw new ArgumentNullException("campaign");
        if (emailAccount == null)
            throw new ArgumentNullException("emailAccount");
        int totalEmailsSent = 0;
        foreach (var subscription in subscriptions)
        {
            var tokens = new List<Token>();
            _messageTokenProvider.AddStoreTokens(tokens);
            _messageTokenProvider.AddNewsLetterSubscriptionTokens(tokens, subscription);
            string subject = _tokenizer.Replace(campaign.Subject, tokens, false);
            string body = _tokenizer.Replace(campaign.Body, tokens, true);
            var email = new QueuedEmail()
            {
                Priority = 3,
                From = emailAccount.Email,
                FromName = emailAccount.DisplayName,
                To = subscription.Email,
                Subject = subject,
                Body = body,
                CreatedOnUtc = DateTime.UtcNow,
                EmailAccountId = emailAccount.Id
            };
            _queuedEmailService.InsertQueuedEmail(email);
            totalEmailsSent++;
            campaignSubscriberTrack.CampaignId = campaign.Id;
            campaignSubscriberTrack.NewsletterSubscriberId = subscription.Id;
            campaignSubscriberTrack.Campaign = campaign;
            campaignSubscriberTrack.NewsletterSubscription = subscription;
            campaignSubscriberTrack.IsEmailOpened = 0;
            campaignSubscriberTrack.OpenedOnUtc = null;
            Guid guid;
            string id = tokens.Where(t => t.Key.Equals("TrackImage")).Select(t => t.Value).FirstOrDefault();
            var lastPart = (id.Split('/').Last()).Split('=').Last();
            if (lastPart != null)
            {
                guid = new Guid(lastPart);
                campaignSubscriberTrack.ImageGUID = guid;
            }
            ***InsertCampaignNewsletterSubscriberTrack(campaignSubscriberTrack);***
        }
        campaign.CampaignSchedulingTime = 0;
        UpdateCampaign(campaign); 
        return totalEmailsSent;
    }

类别-

public partial class CampaignNewsletterSubscriberTrack 
    {
        public virtual Campaign Campaign { get; set; }
        public virtual int CampaignId { get; set; }
        public virtual NewsLetterSubscription NewsletterSubscription { get; set; }
        public virtual int NewsletterSubscriberId { get; set; }
        public virtual int IsEmailOpened { get; set; }
        public virtual DateTime? OpenedOnUtc { get; set; }
        public virtual Guid ImageGUID { get; set; }
    }
}

型号-

public class CampaignNewsletterSubscriberTrackModel
{
    public int CampaignId { get; set; }
    public int NewsletterSubscriberId { get; set; }
    public int IsEmailOpened { get; set; }
    public DateTime? OpenedOnUtc { get; set; }
    public Guid ImageGUID { get; set; }
}

在这个函数中，记录被插入-

public virtual void InsertCampaignNewsletterSubscriberTrack(CampaignNewsletterSubscriberTrack track)
        {
            if (track == null)
                throw new ArgumentNullException("track");
            _campaignNewsletterSubscriberTrackRepository.Insert(track);
        }

错误发生在-->InsertCampaignNewsletter SubscriberTrack（campaignSubscriberTrack）；我该怎么办？？？有人能告诉我哪里出了问题吗？