通用主机中的同步发送/回复

Question

我正在尝试使用通用主机Windows服务的处理函数的同步发送/回复，如下所示。但我认为NServiceBus只在完成句柄功能后才会发送消息（在当前事务完成期间）。所以下面的代码将挂起'synchronousHandle.AsyncWaitHandle.WaitOne（）'。

这里最好的方法是什么？你能指导我......

    Handler constructer

    ConstructorFunction(bus)
    {
                    Bus = bus
    }

    code in the handle function. 
    // sent the message to the bus and wait for the reply

    IMessage response = null;

    var synchronousHandle = Bus.Send(service2queue, requestMessage)
                                            .Register(
                                            (AsyncCallback)delegate(IAsyncResult asyncResult)
                                            {
                                                // Callback block for reply message
                                                // Reply message received
                                                NServiceBus.CompletionResult completionResult = asyncResult.AsyncState as NServiceBus.CompletionResult;
                                                if (completionResult != null && completionResult.Messages.Length > 0)
                                                {
                                                    // Always expecting one IMessage as reply
                                                    response = completionResult.Messages[0];
                                                }
                                            },
                                            null);


// block the current thread till the reply received.
synchronousHandle.AsyncWaitHandle.WaitOne();

谢谢， Ajai

Answer 1

nservicebus试图在不应该做的时候尽可能地努力。

来自nservicebus文档的

：

Bus.Send(request).Register(asyncCallback, state)

Callback only fires on first response, then is cleaned up to prevent memory leaks. 
Doesn’t survive restarts – not suitable for server-side

假设您在服务器端（我猜这里是因为您向我们展示了一个消息处理程序），我会考虑重新设计。

service1 gets a notification about messageA
service1 sends message requestMessage to service2
service2 replies with message responseMessage to service1
service1 handles responseMessage and continues processing

如果您想在继续处理之前等待service1中的多条消息，请尝试考虑实施传真。