static Transaction GetTransactionFromExternalId(Configuration configuration) { // Please see https://docs.transferzero.com/docs/transaction-flow/#external-id // for more details on external IDs TransactionsApi transactionsApi = new TransactionsApi(configuration); String externalId = "TRANSACTION-00001"; TransactionListResponse transactionListResponse = transactionsApi.GetTransactions(externalId: externalId); if (transactionListResponse.Object.Count > 0) { System.Console.WriteLine("Transaction found"); Transaction result = transactionListResponse.Object[0]; System.Console.WriteLine(result); return(result); } else { System.Console.WriteLine("Transaction not found"); return(null); } }