具体报错
The requested operation cannot be completed because the connection has been broken. -- xxxForyyy->Index at System.Data.SqlClient.SqlInternalConnectionTds.ExecuteTransaction(TransactionRequest transactionRequest, String name, IsolationLevel iso, SqlInternalTransaction internalTransaction, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlDelegatedTransaction.Initialize()
at System.Transactions.TransactionStatePSPEOperation.PSPEInitialize(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.TransactionStateActive.EnlistPromotableSinglePhase(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Transaction atomicTransaction, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification)
at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx)
at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx)
at System.Data.SqlClient.SqlInternalConnection.EnlistTransaction(Transaction transaction)
at System.Data.SqlClient.SqlConnection.EnlistTransaction(Transaction transaction)
at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<EnlistTransaction>b__30(DbConnection t, EnlistTransactionInterceptionContext c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action`2 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.EnlistTransaction(DbConnection connection, EnlistTransactionInterceptionContext interceptionContext)
at System.Data.Entity.Core.EntityClient.EntityConnection.EnlistTransaction(Transaction transaction)
错误：正在创建模型，此时不可使用上下文。如果在 OnModelCreating 方法内使用上下文或如果多个线程同时访问同一上下文实例，可能引发此异常。请注意不保证 DbContext 的实例成员和相关类是线程安全的。
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原因可能是并发多线程调用DbContext问题，可以将报错点（Action,AttributeFilter）中的 DbContext 调用换成原生的SqlConnection 试下。