【发布时间】：2017-06-02 16:23:27
【问题描述】：
我已经构建了一个基本的 WCF 控制台服务器应用程序。我的目标是以并行方式处理对它的多个调用，但当前版本按顺序处理它们。
请多多包涵，因为后面会有一堵代码墙，但这是非常基本的东西。我很难隔离，因为它是相当大的 VS 解决方案的一部分。
我已经走上了我基本理解和喜欢的 TPL 和 async/await 关键字的道路。
服务接口：
<ServiceContract()>
Public Interface IGetBackendData
<OperationContract>
Function SendRequest(request As Request) As Task(Of RequestResponse)
<OperationContract>
Function GetNextPackage(serverJobID As Guid) As Task(Of PackageBase)
End Interface
代理：
Public Class imBackendServerProxy
Inherits ClientBase(Of IGetBackendData)
Implements IGetBackendData
Public Function SendRequest(request As Request) As Task(Of RequestResponse) Implements IGetBackendData.SendRequest
Return Channel.SendRequest(request)
End Function
Public Function GetNextPackage(serverJobID As Guid) As Task(Of PackageBase) Implements IGetBackendData.GetNextPackage
Return Channel.GetNextPackage(serverJobID)
End Function
End Class
以及实现：
Public Class GetDataService
Implements IGetBackendData
Private ActiveJobs As New Dictionary(Of Guid, ServiceJobBase)
Private Function ProcessRequest(request As Request) As RequestResponse
Dim newJob As ServiceJobBase
Select Case request.Command.CommandType
Case ImagiroQueryLanguage.CommandTypes.CommandHello
newJob = New HelloJob
Case Else
Throw New ArgumentException("Do not know how to process request")
End Select
If newJob IsNot Nothing Then
newJob.AssignedRequest = request
ActiveJobs.Add(newJob.ID, newJob)
Return newJob.GetResponse()
End If
Throw New ArgumentException("job could not be started")
End Function
Public Async Function SendRequest(request As Request) As Task(Of RequestResponse) Implements IGetBackendData.SendRequest
Console.WriteLine("Request recieved")
Dim mytask As Task(Of RequestResponse) = Task.Factory.StartNew(Function() ProcessRequest(request))
Await Task.Delay(1500)
Return Await mytask.ConfigureAwait(True)
End Function
Private Function GenerateNextPackage(jobid As Guid) As PackageBase
If Not ActiveJobs.ContainsKey(jobid) Then
Throw New ArgumentException("job could Not be found")
End If
Dim nextPackage As PackageBase = ActiveJobs(jobid).GetNextPackage()
If TypeOf (nextPackage) Is PackageEnd Then
ActiveJobs.Remove(jobid)
End If
Return nextPackage
End Function
Public Async Function GetNextPackage(serverTaskID As Guid) As Task(Of PackageBase) Implements IGetBackendData.GetNextPackage
Dim mytask As Task(Of PackageBase) = Task.Factory.StartNew(Of PackageBase)(Function() GenerateNextPackage(serverTaskID))
Await Task.Delay(1500)
Return Await mytask.ConfigureAwait(True)
End Function
End Class
“请求”对象包含“命令”对象（派生自 CommandBase）以及其他信息。
“包”对象（派生自PackageBase）包含要从服务器传输到客户端的数据。
通信应该如何工作的基本思想是这样的：
1. "Request" phase
Client --Request--> Server
Client <--GUID A -- Server
2. "Data" phase
Client -- GUID A --> Server
Client <--DataOrStop-- Server
3. Repeat step 2. until Server says stop.
为了使用数据和请求响应，我有以下类：
Public Class DataReceiver
Public Event DataPackageRecieved(sender As Object, arg As DataPackageReceivedEventArgs)
Public Event EndOfTransmission(sender As Object, arg As EventArgs)
Public Sub New(response As RequestResponse, proxy As imBackendServerProxy, dataRecieved As DataPackageRecievedEventHandler, endOfTransmission As EndOfTransmissionEventHandler)
ID = response.JobID
p = proxy
AddHandler Me.DataPackageRecieved, dataRecieved
AddHandler Me.EndOfTransmission, endOfTransmission
FetchData()
End Sub
Public Property ID As Guid
Private p As imBackendServerProxy
Private Sub FetchData()
Dim t As Task(Of PackageBase) = Task.Factory.StartNew(Of PackageBase)(Function() p.GetNextPackage(ID).Result)
Debug.Print("Waiting for Result FetchData")
t.ContinueWith(AddressOf DoneFetching)
End Sub
Public Delegate Sub ProcessDataPackageDelegate(recievedDataPackage As PackageBase)
Public Property ProcessDataPackage As ProcessDataPackageDelegate
Private Sub DoneFetching(arg As Task(Of PackageBase))
If arg.IsCompleted Then
If TypeOf (arg.Result) Is PackageEnd Then
RaiseEvent EndOfTransmission(Me, Nothing)
Else
RaiseEvent DataPackageRecieved(Me, New DataPackageReceivedEventArgs With {.DataPackage = arg.Result})
FetchData()
End If
End If
End Sub
End Class
在我的 WPF 测试客户端应用程序中，我有一个按钮，我可以用它向服务器发送请求。 HelloCommand（派生自CommandBase）类用于将整数“n”传输到服务器。然后，服务器使用 HelloPackage（派生自 PackageBase）和最后使用 EndPackage（派生自 PackageBase）响应以下 n 个 GetNextPackage 调用中的每一个。
此逻辑在 ServiceJob 对象（派生自 ServiceJobBase）中处理 - 基本上每个“命令”对象都有一个相应的“ServiceJob”对象，该对象反过来将相应的“包”对象发送到顺序客户端请求。
由于客户端处理“数据请求”所需的“顺序性”，即对GetNextPackage 函数的顺序调用，这些调用将永远不会重叠。但我非常希望对GetNextPackage 及其各自的“ServiceJobs”的两个或多个单独的调用序列在服务器上并行执行。而这并没有发生。
向HelloServiceJob 类添加一个简单的计数器以轻松识别每个请求，在我的 WPF 客户端中按一下按钮会在服务器上产生以下输出，同时 UI 保持响应。
Request recieved (0)
Sending HelloPackage - 6 remaining (0)
Sending HelloPackage - 5 remaining (0)
Sending HelloPackage - 4 remaining (0)
Sending HelloPackage - 3 remaining (0)
Sending HelloPackage - 2 remaining (0)
Sending HelloPackage - 1 remaining (0)
Sending HelloPackage - 0 remaining (0)
Sending no more HelloPackages
如预期的那样，每行之间有 1.5 秒。
连续快速按三下会在服务器上产生以下输出，同时 UI 保持响应。
Request recieved (1)
Request recieved (2)
Request recieved (3)
Sending HelloPackage - 6 remaining (1)
Sending HelloPackage - 6 remaining (2)
Sending HelloPackage - 6 remaining (3)
Sending HelloPackage - 5 remaining (1)
Sending HelloPackage - 5 remaining (2)
Sending HelloPackage - 5 remaining (3)
Sending HelloPackage - 4 remaining (1)
Sending HelloPackage - 4 remaining (2)
Sending HelloPackage - 4 remaining (3)
Sending HelloPackage - 3 remaining (1)
Sending HelloPackage - 3 remaining (2)
Sending HelloPackage - 3 remaining (3)
Sending HelloPackage - 2 remaining (1)
Sending HelloPackage - 2 remaining (2)
Sending HelloPackage - 2 remaining (3)
Sending HelloPackage - 1 remaining (1)
Sending HelloPackage - 1 remaining (2)
Sending HelloPackage - 1 remaining (3)
Sending HelloPackage - 0 remaining (1)
Sending HelloPackage - 0 remaining (2)
Sending HelloPackage - 0 remaining
Sending no more HelloPackages (1)
Sending no more HelloPackages (2)
Sending no more HelloPackages (3)
虽然订单是预期的，但每行执行需要 1.5 秒，客户端和服务器一次只交换消息。
看了很多文章，我比什么都困惑。我无法确定我需要做什么才能使三个“作业”并行执行，即使这是完全错误的方法还是简单的配置错误。
我在同一台机器上运行服务器和客户端，使用netTcpBinding，如果我理解正确，它适用于客户端和服务器之间的多个并行请求。
我已阅读并（希望）理解以下文章，但我不明白这如何转化为我的案例：tasks are still not threads and async is not parallel
我怎样才能让正在接听电话的作业在不同的线程上运行呢？我完全知道Return Await 语句只是等待执行完成，但这不是问题。我想要的是其中三个语句等待并行完成，但服务器和客户端之间的管道似乎一次只保存一条消息？
感谢大家的时间和投入，我真的很感激。
【问题讨论】：
标签： vb.net multithreading wcf asynchronous task-parallel-library