vb.Net-命名管道-NamedPipeServerStream-StackOverflowException

Question

我正在尝试使用命名管道在 Windows 服务和 WPF 应用程序之间进行通信，两者都是用 VB.Net 编写的。 Windows 服务一直在运行。

但是，在运行 WPF 应用程序几个小时后，会抛出 StackOverflowException。

WPF 应用程序中的PipeServerThread() 是唯一在异常发生时在托管堆栈中被重复调用的函数（我使用WinDbg 跟踪了这一点）。

服务包含NamedPipeClientStream，应用包含NamedPipeServerStream。

当客户端和服务器通信时，服务器在经过几次检查后读取最终的客户端响应，然后将客户端字符串传递给代码中其他地方的函数。

然后管道服务器被刷新、关闭和处置。

然后再次调用PipeServerThread() 以创建另一个用于通信的管道服务器。注意这个 PipeServerThread() 被重复调用。

谁能阐明代码中的什么最终导致StackOverflowException 发生？

管道服务器：

Dim PipeServers(1) As Thread
PipeServers(1) = New Thread(AddressOf PipeServerThread)
PipeServers(1).IsBackground = True
PipeServers(1).Start()

Private Sub PipeServerThread()

    Dim ps = New System.IO.Pipes.PipeSecurity

    Try
        ps.AddAccessRule(New System.IO.Pipes.PipeAccessRule("Users", System.IO.Pipes.PipeAccessRights.FullControl, System.Security.AccessControl.AccessControlType.Allow))
        ps.AddAccessRule(New System.IO.Pipes.PipeAccessRule("CREATOR OWNER", System.IO.Pipes.PipeAccessRights.FullControl, System.Security.AccessControl.AccessControlType.Allow))
        ps.AddAccessRule(New System.IO.Pipes.PipeAccessRule("SYSTEM", System.IO.Pipes.PipeAccessRights.FullControl, System.Security.AccessControl.AccessControlType.Allow))

        Dim pipeserver = New System.IO.Pipes.NamedPipeServerStream("testpipe", Pipes.PipeDirection.InOut, 10, Pipes.PipeTransmissionMode.Byte, Pipes.PipeOptions.None, 4024, 4024, ps)

        Debug.WriteLine("Pipeserver waiting for connection")
        pipeserver.WaitForConnection()
        Try
            'Debug.WriteLine("Pipeserver now within Try block.")
            Dim ss As New StreamString(pipeserver)
            'This server writes to pipe immediately on connection
            Debug.WriteLine("Server now writing to Pipe")
            ss.WriteString("Hello Client. Who are you?")                                            'Action 1 - server writes to Pipe

            'Response from client is read
            Dim ClientName As String = ss.ReadString                                                'Action 4 - server reads from Pipe
            Debug.WriteLine("Client's name is: " & ClientName)
            If ClientName = "PipeWriterService" Then
                'The client is the PipeWriterService
                'Tell it what state is being requested
                ss.WriteString(RequestedCommState)                                                  'Action 5 (if) - server writes to Pipe
            Else
                'The client is someting else
                ss.WriteString("wrong client")                                                      'Action 5 (else) - server writes to Pipe
            End If

            Dim ClientResponse As String = ss.ReadString()
            Debug.WriteLine("Server has read client Response as: " & ClientResponse)                'Action 8 - server reads from Pipe
            DeviceInfo.Dispatcher.BeginInvoke(Windows.Threading.DispatcherPriority.Normal, New OneArgDelegate3(AddressOf ProcessPipeString), ClientResponse)
        Catch ex As Exception
            Debug.WriteLine("Error is Server Try block: " & ex.Message)
        End Try
        pipeserver.Flush()
        pipeserver.Close()                                                                          'Action 9 - server closes Pipe
        pipeserver.Dispose()
        Debug.WriteLine("PipeServer now closed")
    Catch ex As Exception

    End Try

    Call PipeServerThread()
End Sub

管道客户端：

    Private Sub PipeWriter(StringToWrite As String)
    Dim pipeClient As New NamedPipeClientStream(".", "testpipe", PipeDirection.InOut, PipeOptions.None)
    Try
        pipeClient.Connect(50)
        Dim ss As New StreamString(pipeClient)
        'Once a connection is established, Server will write to pipe first
        'This is read by the client in the line below
        Debug.WriteLine("First string from Server: " & ss.ReadString())                             'Action 2: Client Reads from Pipe
        'Server is now waiting. This client responds with its name
        ss.WriteString("PipeWriterService")                                                           'Action 3: Client Writes to Pipe
        'Server will respond again
        'This is read by the client in the line below
        RequestedCommState = ss.ReadString()                                                    'Action 6: Client reads from Pipe
        Debug.WriteLine("Second string from Server: " & RequestedCommState)
        'This response contains the desired 3G comm status from the server
        'Server is now waiting. This client responds with whatever it wants to say to server
        ss.WriteString(StringToWrite)                                                               'Action 7: Client writes to Pipe
    Catch ex As Exception
        Debug.WriteLine("Error in PipeWriter. Error is: " & ex.Message)
    End Try

End Sub

Answer 1

此时您可能已经解决了问题。

无论如何，问题是在 PipeServerThread() 的递归调用。每次调用它时，堆栈的大小都会增加以保存局部变量和函数的返回地址。

你必须摆脱递归调用并将函数体放入循环中。