问实体框架中的SqlException， 不允许新的Business，因为会话中还有其他线程正在运行？

public class ProductManager : IProductManage

{

    #region Declare Models

    private RivWorks.Model.Negotiation.RIV_Entities _dbRiv = RivWorks.Model.Stores.RivEntities(AppSettings.RivWorkEntities_connString);

    private RivWorks.Model.NegotiationAutos.RivFeedsEntities _dbFeed = RivWorks.Model.Stores.FeedEntities(AppSettings.FeedAutosEntities_connString);

    #endregion

    public IProduct GetProductById(Guid productId)

    {

        // Do a quick sync of the feeds...

        SyncFeeds();

        ...

        // get a product...

        ...

        return product;

    }

    private void SyncFeeds()

    {

        bool found = false;

        string feedSource = "AUTO";

        switch (feedSource) // companyFeedDetail.FeedSourceTable.ToUpper())

        {

            case "AUTO":

                var clientList = from a in _dbFeed.Client.Include("Auto") select a;

                foreach (RivWorks.Model.NegotiationAutos.Client client in clientList)

                {

                    var companyFeedDetailList = from a in _dbRiv.AutoNegotiationDetails where a.ClientID == client.ClientID select a;

                    foreach (RivWorks.Model.Negotiation.AutoNegotiationDetails companyFeedDetail in companyFeedDetailList)

                    {

                        if (companyFeedDetail.FeedSourceTable.ToUpper() == "AUTO")

                        {

                            var company = (from a in _dbRiv.Company.Include("Product") where a.CompanyId == companyFeedDetail.CompanyId select a).First();

                            foreach (RivWorks.Model.NegotiationAutos.Auto sourceProduct in client.Auto)

                            {

                                foreach (RivWorks.Model.Negotiation.Product targetProduct in company.Product)

                                {

                                    if (targetProduct.alternateProductID == sourceProduct.AutoID)

                                    {

                                        found = true;

                                        break;

                                    }

                                }

                                if (!found)

                                {

                                    var newProduct = new RivWorks.Model.Negotiation.Product();

                                    newProduct.alternateProductID = sourceProduct.AutoID;

                                    newProduct.isFromFeed = true;

                                    newProduct.isDeleted = false;

                                    newProduct.SKU = sourceProduct.StockNumber;

                                    company.Product.Add(newProduct);

                                }

                            }

                            _dbRiv.SaveChanges(); // ### THIS BREAKS ### //

                        }

                    }

                }

                break;

        }

    }

}