问EF6事务

EN

     public DepositTransaction DepositAdd(int userId, decimal ammount)
    {
        using (var cx = this.Database.GetDbContext())
        {
            using (var trx = cx.Database.BeginTransaction(System.Data.IsolationLevel.RepeatableRead))
            {
                try
                {
                    //here the last deposit ammount is read and new created with same context
                    var transaction = this.DepositTransaction(userId, ammount, SharedLib.BalanceTransactionType.Deposit, cx);
                    trx.Commit();
                    return transaction;
                }
                catch
                {
                    trx.Rollback();
                    throw;
                }
            }                    
        }
    }