在参考 Dead-Letter-Exchange 进行Dead-letter-exchange的理解，

在本地时，想要创建 Dead-letter-exchange 时，一直报错，错误如下：

Unhandled Exception: RabbitMQ.Client.Exceptions.OperationInterruptedException: The AMQP operation was interrupted: AMQP close-reason, initiated by Peer, code=406, text="PRECONDITION_FAILED - inequivalent arg 'x-dead-letter-exchange' for queue 'q_test' in vhost '/': received the value 'q-dead-letter-exchange' of type 'longstr' but current is none", classId=50, methodId=10, cause=

   at RabbitMQ.Client.Impl.SimpleBlockingRpcContinuation.GetReply(TimeSpan timeout)

   at RabbitMQ.Client.Impl.ModelBase.QueueDeclare(String queue, Boolean passive, Boolean durable, Boolean exclusive, Boolean autoDelete, IDictionary`2 arguments)

   at RabbitMQ.Client.Impl.AutorecoveringModel.QueueDeclare(String queue, Boolean durable, Boolean exclusive, Boolean autoDelete, IDictionary`2 arguments)

   at CNBlogs.Question.EventBusRabbitMQ.EventBusRabbitMQ.CreateConsumerChannel()

去官网查了查，姿势也正确，先声明一个Exchange

channel.ExchangeDeclare("q-dead-letter-exchange", type: "direct");

然后再指定 x-dead-letter-exchange 参数

var args = new Dictionary<string, object>()

            {

                {"x-dead-letter-exchange", "q-dead-letter-exchange"}

            };

最后放到队列声明里面：

 channel.QueueDeclare(queue: _queueName,

                                 durable: true,

                                 exclusive: false,

                                 autoDelete: false,

                                 arguments: args);

然而，每次一运行就报上面那个错误，最后子啊Github上找到了答案

• using a dead letter exchange

原因可能是我原来的队列中，因为有尚未确认的消息在。然后，把RabbitMQ 中的Queue 和Exchange 删除，重新运行程序就成功了。下面是Queue和Exchange 的截图