Visual Studio 生成的 Web 服务客户端线程安全吗？

Question

我们在其中一个项目中创建了服务引用。

现在我们在应用程序启动时创建一个 this 的实例。 此外，当应用程序统计时，我们为Service.Method1Completed、Service.Method2Completed 等添加事件处理程序。

然后在特定事件上，我们调用Service.Method1Async、Service.Method2Async 等。请注意，这些调用是由不同的线程发出的。

但在某些计算机上，事件处理程序从未被触发，因此我们开始检查 FirstChanceExceptions，因为当这种情况发生时，会发生以下 FirstChanceExceptions。

System.Net.Sockets.SocketException 提供的参数无效。
vid System.Net.Sockets.Socket.SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, Int32 optionValue, Boolean 沉默）

System.ObjectDisposedException 无法访问已处置的对象。 对象名：System.Net.Sockets.NetworkStream。视频 System.Net.Sockets.NetworkStream.UnsafeBeginWrite（字节 [] 缓冲区，Int32 偏移量、Int32 大小、AsyncCallback 回调、对象状态）

System.Net.WebException 请求被取消。
vid System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)

这是使用服务参考的无效方式吗？ 如果是我如何在使用带有事件的异步方法时正确使用同步我的调用（注意我在 .net 4.0 和 VS 2010 上很烂，所以await 不在图片中......）。

服务器代码：

<ServiceContract()>
Public Interface IService1

    <OperationContract()>
    Function GetData(ByVal value As Integer) As String

End Interface

<ServiceBehavior(ConcurrencyMode:=ConcurrencyMode.Multiple, InstanceContextMode:=InstanceContextMode.Single, UseSynchronizationContext:=False)>
Public Class Service1
    Implements IService1

    Public Sub New()
    End Sub

    Public Function GetData(ByVal value As Integer) As String Implements IService1.GetData
        Return String.Format("You entered: {0}", value)
    End Function

End Class

服务器配置：

<system.serviceModel>
  <behaviors>
    <serviceBehaviors>
      <behavior>
        <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
        <serviceMetadata httpGetEnabled="true"/>
        <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
        <serviceDebug includeExceptionDetailInFaults="false"/>
        <serviceThrottling maxConcurrentCalls="1000" maxConcurrentSessions="1000" maxConcurrentInstances="1000" />
      </behavior>
    </serviceBehaviors>
  </behaviors>
  <bindings>
    <customBinding>
      <binding>
        <binaryMessageEncoding>
          <readerQuotas maxArrayLength="5242880" />
        </binaryMessageEncoding>
        <httpTransport maxBufferPoolSize="52428800" maxReceivedMessageSize="5242880" maxBufferSize="5242880" authenticationScheme="Anonymous" />
      </binding>
    </customBinding>
  </bindings>
  <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
</system.serviceModel>

客户端代码：

Imports System.Threading
Imports System.IO

Module Module1
    Dim errorQueue As New System.Collections.Concurrent.ConcurrentBag(Of String)
    Dim count As Integer

    Sub Main()
        AddHandler AppDomain.CurrentDomain.UnhandledException, AddressOf CurrentDomain_UnhandledException
        AddHandler AppDomain.CurrentDomain.FirstChanceException, AddressOf AppDomain_FirstChanceException

        MultipleClientInstances()
        Console.WriteLine("Calls are in progress, press any key when they are done!")
        Console.ReadKey()

        Thread.MemoryBarrier()
        errorQueue.Add("Number of requests remaining " + count.ToString())
        Dim line As String = ""
        Using writer As New StreamWriter("output.log")
            While (errorQueue.TryTake(line))
                writer.WriteLine(line)
            End While
        End Using
    End Sub

    Private Function GetClient() As ServiceReference1.Service1Client
        Dim client As New ServiceReference1.Service1Client()
        AddHandler client.GetDataCompleted, AddressOf client_GetDataCompleted
        client.Open()
        Return client
    End Function

    Private Sub MultipleClientInstances()
        Console.WriteLine("Making calls!")
        For i As Integer = 0 To 10
            Dim t As New Thread(AddressOf MakeCallsWithNewClients)
            t.Start()
        Next
    End Sub

    Private Sub MakeCallsWithNewClients()
        For i As Integer = 0 To 400
            Interlocked.Increment(count)
            Dim client As ServiceReference1.Service1Client = GetClient()
            client.GetDataAsync(i, True)

            While (Thread.VolatileRead(count) > 20)
                Thread.Sleep(5)
            End While
        Next
    End Sub

    Private Sub client_GetDataCompleted(sender As Object, e As ServiceReference1.GetDataCompletedEventArgs)
        Dim value As Integer = Interlocked.Decrement(count)
        Console.WriteLine(value)

        Dim client As ServiceReference1.Service1Client = CType(sender, ServiceReference1.Service1Client)
        RemoveHandler client.GetDataCompleted, AddressOf client_GetDataCompleted
        client.Close()
    End Sub

    Private Sub CurrentDomain_UnhandledException(ByVal sender As Object, ByVal e As UnhandledExceptionEventArgs)
        If (e.ExceptionObject IsNot Nothing AndAlso e.ExceptionObject.GetType().IsSubclassOf(GetType(Exception))) Then
            If (e.IsTerminating) Then
                Console.WriteLine("Fatal exception occurred termination application, " + CType(e.ExceptionObject, Exception).ToString())
            Else
                Console.WriteLine("Unhandled exception occurred, " + CType(e.ExceptionObject, Exception).ToString())
            End If
        Else
            If (e.IsTerminating) Then
                Console.WriteLine("Fatal exception occurred termination application, " & e.ExceptionObject.ToString())
            Else
                Console.WriteLine("Unhandled exception occurred, " & e.ExceptionObject.ToString())
            End If
        End If
        errorQueue.Add("UnhandledException: " + e.ExceptionObject.ToString())
    End Sub

    Private Sub AppDomain_FirstChanceException(ByVal sender As Object, ByVal e As Runtime.ExceptionServices.FirstChanceExceptionEventArgs)
        Console.WriteLine("FirstChanceException: " + e.Exception.ToString())
        errorQueue.Add("FirstChanceException: " + e.Exception.ToString())
    End Sub
End Module

Answer 1

它们不是线程安全的（例如ClientBase 不是）。但是它们的创建和销毁成本很低。每个线程创建一个，甚至每个调用创建一个。无需同步。

Answer 2

ClientBase 可能不是线程安全的*，因此派生代理也不是，因此您不能以这种方式使用它们。

您可以创建一个线程安全的基类并自定义生成代理类。

state 参数可用于将响应与传出请求匹配。您会在回调事件的 IAsyncResult.AsyncState 中找到它。

要担心的一件事是，当多个请求通过同一个通道发送并且通道由于某些/任何原因而出现故障时。

*也看看这个问题：Is WCF ClientBase thread safe?