问EntityFramework.BulkInsert抛出KeyNotFoundException

EN

        using (var context = new SupportContext(request.CustomerId))
        {
            using (var transactionScope = new TransactionScope())
            {
                var freeIds =
                    Enumerable.Range(1, 89999)
                        .Except(
                            context.TagAssociationTypes.Where(n => n.TagAssociationTypeID <= 89999)
                                .Select(n => n.TagAssociationTypeID))
                        .ToList();
                var nfeList = context.NumericalFunctionEnums.ToList();
                var processedTats = new List<TagAssociationType>();
                foreach (var item in request.Tats)
                {
                    var groupingNFE = nfeList.FirstOrDefault(n => n.nfe_description == item.GroupingNFE.Value);
                    var summaryNFE = nfeList.FirstOrDefault(n => n.nfe_description == item.SummaryNFE.Value);
                    var tatId = freeIds.Min();

                    var newItem = new TagAssociationType
                    {
                        TagAssociationTypeID = tatId,
                        Name = item.TagAssociationTypeName.Value,
                        GroupingFunctionID = groupingNFE != null ? groupingNFE.nfe_id : 0,
                        SummaryFunctionID = summaryNFE!= null ? summaryNFE.nfe_id : 0
                    };

                    processedTats.Add(newItem);
                    freeIds.Remove(tatId);
                }
                context.BulkInsert(processedTats);
                transactionScope.Complete();
            }
        }

System.Collections.Generic.KeyNotFoundException was unhandled by user code
  HResult=-2146232969
  Message=The given key was not present in the dictionary.
  Source=mscorlib
  StackTrace:
       at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
       at EntityFramework.MappingAPI.Mappers.MapperBase.BindForeignKeys() in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Mappers\MapperBase.cs:line 603
       at EntityFramework.MappingAPI.Mappings.DbMapping..ctor(DbContext context) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Mappings\DbMapping.cs:line 101
       at EntityFramework.MappingAPI.EfMap.Get(DbContext context) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\EfMap.cs:line 60
       at EntityFramework.MappingAPI.Extensions.MappingApiExtensions.Db(DbContext ctx, Type type) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Extensions\MappingApiExtensions.cs:line 51
       at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
       at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
       at EntityFramework.BulkInsert.Helpers.MappedDataReader`1..ctor(IEnumerable`1 enumerable, IEfBulkInsertProvider provider) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Helpers\MappedDataReader.cs:line 58
       at EntityFramework.BulkInsert.Providers.EfSqlBulkInsertProviderWithMappedDataReader.Run[T](IEnumerable`1 entities, SqlTransaction transaction, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\EfSqlBulkInsertProviderWithMappedDataReader.cs:line 22
       at EntityFramework.BulkInsert.Providers.ProviderBase`2.Run[T](IEnumerable`1 entities, IDbTransaction transaction, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\ProviderBase.cs:line 77
       at EntityFramework.BulkInsert.Providers.ProviderBase`2.Run[T](IEnumerable`1 entities, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\ProviderBase.cs:line 105
       at EntityFramework.BulkInsert.Extensions.BulkInsertExtension.BulkInsert[T](DbContext context, IEnumerable`1 entities, SqlBulkCopyOptions sqlBulkCopyOptions, Nullable`1 batchSize) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Extensions\BulkInsertExtension.cs:line 95
       at EntityFramework.BulkInsert.Extensions.BulkInsertExtension.BulkInsert[T](DbContext context, IEnumerable`1 entities, Nullable`1 batchSize) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Extensions\BulkInsertExtension.cs:line 75
       at SupportCenter.Controllers.Api.BulkLocalTatController.InsertTats(VerifyQuery request)
       at lambda_method(Closure , Object , Object[] )
       at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
       at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
       at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)
  InnerException: