我有一个旧版 (2008) Windows 服务应用程序（使用 System.ServiceProcess.ServiceBase），我需要以与它现在的工作方式略有不同的方式使用它。目前它启动并在特定端口上创建一个 TCPLISTENER，供客户端应用程序连接（它只做一次），以便向侦听端口发送/接收请求。这一切都很好。但是，适配需要使用 web 应用程序连接到侦听器端口，然后正常发送/rcv，但接收后必须 DISCONNECT(*)
（* - 如果 Web 应用程序不必在每次测试后断开与侦听套接字的连接会更好，但我如何实现这一点超出了我的能力范围。我可以将 TCP 连接保持在会话状态以供重复使用吗？ )
无论如何，对于前两个connect/send/rcv/disconnect 测试，适配都可以正常工作，但在第三个服务中，服务会在 Socket 类的 EndAccept 中引发 ArgumentException。
我不明白为什么它在第三次测试中失败了。
这是简单的测试客户端。
Public Class ConnectDisconnectTCP
Inherits System.Web.UI.Page
Private IP As String = "127.0.0.1"
Private port As Int32 = 10002
Private mTCP As System.Net.Sockets.TcpClient
Private netStrm As NetworkStream
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim oEnc As New ASCIIEncoding
Dim ScanText As String = "100000000093001X" + vbLf
Dim mTCP As System.Net.Sockets.TcpClient
'connect and create a tcpclient
mTCP = New System.Net.Sockets.TcpClient(IP, port)
netStrm = mTCP.GetStream()
netStrm.WriteAsync(oEnc.GetBytes(ScanText.ToString), 0, ScanText.ToString.Length)
If netStrm.CanRead Then
Dim myReadBuffer(1024) As Byte
Dim myCompleteMessage As StringBuilder = New StringBuilder()
Dim numberOfBytesRead As Integer = 0
' Incoming message may be larger than the buffer size.
Do
numberOfBytesRead = netStrm.Read(myReadBuffer, 0, myReadBuffer.Length)
myCompleteMessage.AppendFormat("{0}", Encoding.ASCII.GetString(myReadBuffer, 0, numberOfBytesRead))
Loop While netStrm.DataAvailable
End If
'CLOSE
netStrm.Close()
mTCP.Close() 'Disposes this TcpClient instance and requests that the underlying TCP connection be closed.
mTCP = Nothing
Label1.Text = "Closed"
End Sub End Class
这是完成所有工作的服务上的 TCPListener 类
Imports System
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.Text
Public Class TCPListenerPort
Private currentAsynchResult As IAsyncResult
Private cState As ClientState
Private servSock As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
Private m_connectionstate As Int32 = 0
Dim sData As String = String.Empty
'counters
Public cnt As Int32 = 0
Public rcvcnt As Int32 = 0
Public acccnt As Int32 = 0
Public sndcnt As Int32 = 0
Public sndcal As Int32 = 0
Public cncnt As Int32 = 0
'Public Events
Public Event ConnectionState(ByVal enmState As Int32)
Public Event DataArrived(ByVal strData As Object)
Public Sub New()
End Sub
Public Sub New(ByVal dr As DataRow)
End Sub
Protected Overrides Sub Finalize()
Try
If Not cState Is Nothing Then
cState.ClntSock.Close()
End If
If Not servSock Is Nothing Then
servSock.Close()
End If
Catch ex As Exception
Throw ex
Finally
MyBase.Finalize()
End Try
End Sub
Private Class ClientState
Public Const BUFSIZE As Integer = 1024
Public mrcvBuffer As Byte() = New Byte(BUFSIZE - 1) {}
Public mSendBuffer As Byte() = New Byte(BUFSIZE - 1) {}
Private mclntSock As Socket = Nothing
Public Sub New(ByRef clntSock As Socket)
mclntSock = clntSock
ReDim mrcvBuffer(BUFSIZE)
ReDim mSendBuffer(BUFSIZE)
End Sub
Public ReadOnly Property SckConnected() As Boolean
Get
SckConnected = mclntSock.Connected
End Get
End Property
Public ReadOnly Property RcvBuffer() As Byte()
Get
RcvBuffer = mrcvBuffer
End Get
End Property
Public ReadOnly Property SendBuffer() As Byte()
Get
SendBuffer = mSendBuffer
End Get
End Property
Public ReadOnly Property ClntSock() As Socket
Get
ClntSock = mclntSock
End Get
End Property
End Class
Public Sub Connect(ByVal TCPPort As Int32, ByVal Backlog As Int32)
Try
cState = New ClientState(servSock)
cState.ClntSock.Bind(New IPEndPoint(System.Net.IPAddress.Any, TCPPort))
cState.ClntSock.Listen(100) '5
While True
cncnt = cncnt + 1
System.Diagnostics.Debug.WriteLine("in connect WHILE " + cncnt.ToString)
currentAsynchResult = servSock.BeginAccept(New AsyncCallback(AddressOf AcceptCallback), cState)
currentAsynchResult.AsyncWaitHandle.WaitOne()
End While
Catch __unusedObjectDisposedException1__ As ObjectDisposedException
Catch e As Exception
End Try
End Sub
Private Sub AcceptCallback(ByVal asyncResult As IAsyncResult)
Try
acccnt = acccnt + 1
System.Diagnostics.Debug.WriteLine("AcceptCallback Start" + acccnt.ToString)
'obtain the Socket on which the connection attempt is being made
Dim servSock As ClientState = asyncResult.AsyncState 'Asyncstate gets a user defined object that qualifies or contains info about an async operation
Dim clntSock As Socket
clntSock = servSock.ClntSock.EndAccept(asyncResult)
System.Diagnostics.Debug.WriteLine(clntSock.RemoteEndPoint)
Dim cs As New ClientState(clntSock)
clntSock.BeginReceive(cs.RcvBuffer, 0, cs.RcvBuffer.Length, SocketFlags.None, New AsyncCallback(AddressOf ReceiveCallback), cs)
Catch ar As ArgumentException
'!!!!!Test 3 errors here with
'The IAsyncResult object was not returned from the corresponding asynchronous method on this class.
Catch ex As Exception
End Try
System.Diagnostics.Debug.WriteLine("AcceptCallback End " + acccnt.ToString)
End Sub
Private Sub ReceiveCallback(ByVal asyncResult As IAsyncResult)
rcvcnt = rcvcnt + 1
System.Diagnostics.Debug.WriteLine("ReceiveCallback In " + rcvcnt.ToString)
Dim cs As ClientState = asyncResult.AsyncState
Dim AE As New System.Text.ASCIIEncoding
Dim recvMsgSize As Int32 = 0
Dim strTmp As String = String.Empty
Dim strSend As String = String.Empty
Try
recvMsgSize = cs.ClntSock.EndReceive(asyncResult)
strTmp = Replace(AE.GetString(cs.RcvBuffer), vbNullChar, "")
If recvMsgSize > 0 Then
System.Diagnostics.Debug.WriteLine("ReceiveCallback receiveMsgSize " + recvMsgSize.ToString)
If Right(strTmp, 1) = vbLf Or Right(strTmp, 1) = vbCr Then
strSend = sData + strTmp
strSend = strSend.Replace(vbLf, "")
strSend = strSend.Replace(vbCr, "")
cState = cs
sData = String.Empty
RaiseEvent DataArrived(strSend)
Else
End If
Else
End If
Catch ex As Exception
Throw ex
End Try
System.Diagnostics.Debug.WriteLine("ReceiveCallback Exit " + rcvcnt.ToString)
End Sub
Public Function SendData(ByVal strData As Object) As Boolean
' Change the data to a byte array if necessary, then send it via the socket
Dim oEncoder As New System.Text.ASCIIEncoding
Dim bytes As Byte()
Dim Result As IAsyncResult
Try
Select Case strData.GetType().ToString
Case "System.String" ' Convert a string to a byte array
bytes = oEncoder.GetBytes(strData)
Case "System.Byte[]" ' Send a byte array directly
bytes = strData
Case Else ' And just send anything else as-is
bytes = strData
End Select
sndcnt = sndcnt + 1
Result = cState.ClntSock.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, New AsyncCallback(AddressOf SendCallback), cState)
System.Diagnostics.Debug.WriteLine("SendData " + sndcnt + " " + Result.ToString)
Result.AsyncWaitHandle.WaitOne()
Catch ex As Exception
Throw ex
End Try
Return True
End Function
Private Sub SendCallback(ByVal asyncResult As IAsyncResult)
Dim cs As ClientState = asyncResult.AsyncState
Dim bytesSent As Int32 = 0
Try
bytesSent = cs.ClntSock.EndSend(asyncResult)
sndcal = sndcal + 1
cs.ClntSock.BeginReceive(cs.RcvBuffer, 0, cs.RcvBuffer.Length, SocketFlags.None, New AsyncCallback(AddressOf ReceiveCallback), cs)
System.Diagnostics.Debug.WriteLine("SendCallBack " + sndcal.ToString + " " + bytesSent.ToString)
Catch ex As Exception
Throw (ex)
End Try
End Sub
End Class
打开 .net 跟踪，加上代码的系统诊断 debug.write，这里是 TEST1、TEST2、TEST3/CRASH 操作的完整日志。注意 '<-- SCANTEXT RECEIVED' 和 '<-- RESPONSE RECEIVED' 注释。'in connect WHILE 4' 注释显示了第三次请求尝试的到达。
[12572] TcpClient#57416410::TcpClient(AddressFamily#2)
[12572] Socket#61940669::Socket(AddressFamily#2)
[12572] Exiting Socket#61940669::Socket()
[12572] Exiting TcpClient#57416410::TcpClient()
[12572] TcpClient#57416410::TcpClient()
[12572] Exiting TcpClient#57416410::TcpClient()
[12572] Socket#15193904::Socket(AddressFamily#2)
[12572] Exiting Socket#15193904::Socket()
[17872] Socket#40528290::Socket(AddressFamily#2)
[17872] Exiting Socket#40528290::Socket()
[17872] Socket#40528290::Bind(0.0.0.0:10002#10002)
[17872] Exiting Socket#40528290::Bind()
[17872] Socket#40528290::Listen(Int32#100)
[17872] Exiting Socket#40528290::Listen()
in connect WHILE 1
[17872] Socket#40528290::BeginAccept()
[17872] Exiting Socket#40528290::BeginAccept() -> AcceptAsyncResult#515737
The thread '1' (0x6674) has exited with code 0 (0x0).
The thread '<No Name>' (0x1df8) has exited with code 0 (0x0).
The thread '<No Name>' (0x5dac) has exited with code 0 (0x0).
[7984] Socket#49538252::Socket()
[7984] Exiting Socket#49538252::Socket()
in connect WHILE 2
AcceptCallback Start1
[17872] Socket#40528290::BeginAccept()
[7984] Socket#40528290::EndAccept(AcceptAsyncResult#515737)
[17872] Exiting Socket#40528290::BeginAccept() -> AcceptAsyncResult#27334100
System.Net.Sockets Information: 0 : [7984] Socket#49538252 - Accepted connection from 127.0.0.1:63817 to 127.0.0.1:10002.
[7984] Exiting Socket#40528290::EndAccept() -> Socket#49538252
127.0.0.1:63817
[7984] Socket#49538252::BeginReceive()
[7984] Exiting Socket#49538252::BeginReceive() -> OverlappedAsyncResult#62696216
AcceptCallback End 1
[22168] Data from Socket#49538252::PostCompletion
[22168] 00000000 : 32 30 30 30 30 30 30 30-30 30 38 33 30 30 31 58 : 100000000093001X <-- SCANTEXT RECEIVED, TEST1
[22168] 00000010 : 0A : .
ReceiveCallback In 1
[22168] Socket#49538252::EndReceive(OverlappedAsyncResult#62696216)
[22168] Exiting Socket#49538252::EndReceive() -> Int32#17
ReceiveCallback receiveMsgSize 17
[22168] Socket#49538252::BeginSend()
[22168] Exiting Socket#49538252::BeginSend() -> OverlappedAsyncResult#13462887
A first chance exception of type 'System.FormatException' occurred in Microsoft.VisualBasic.dll
[19228] Data from Socket#49538252::PostCompletion
[19228] 00000000 : 07 : . <-- RESPONSE RECEIVED, TEST1
[19228] Socket#49538252::EndSend(OverlappedAsyncResult#13462887)
[19228] Exiting Socket#49538252::EndSend() -> Int32#1
[19228] Socket#49538252::BeginReceive()
[19228] Exiting Socket#49538252::BeginReceive() -> OverlappedAsyncResult#25961440
SendCallBack 1 1
[7984] Data from Socket#49538252::PostCompletion
[7984] 00000000 : :
ReceiveCallback In 2
[7984] Socket#49538252::EndReceive(OverlappedAsyncResult#25961440)
[7984] Exiting Socket#49538252::EndReceive() -> Int32#0
ReceiveCallback Exit 2
ReceiveCallback Exit 2
[22168] Socket#31352595::Socket()
[22168] Exiting Socket#31352595::Socket()
AcceptCallback Start2
in connect WHILE 3
[17872] Socket#40528290::BeginAccept()
[22168] Socket#40528290::EndAccept(AcceptAsyncResult#27334100)
[17872] Exiting Socket#40528290::BeginAccept() -> AcceptAsyncResult#39421196
System.Net.Sockets Information: 0 : [22168] Socket#31352595 - Accepted connection from 127.0.0.1:63820 to 127.0.0.1:10002.
[22168] Exiting Socket#40528290::EndAccept() -> Socket#31352595
127.0.0.1:63820
[22168] Socket#31352595::BeginReceive()
[22168] Exiting Socket#31352595::BeginReceive() -> OverlappedAsyncResult#28002689
AcceptCallback End 2
[7984] Data from Socket#31352595::PostCompletion
[7984] 00000000 : 32 30 30 30 30 30 30 30-30 30 38 33 30 30 31 58 : 100000000093001X <-- SCANTEXT RECEIVED, TEST2
[7984] 00000010 : 0A : .
ReceiveCallback In 3
[7984] Socket#31352595::EndReceive(OverlappedAsyncResult#28002689)
[7984] Exiting Socket#31352595::EndReceive() -> Int32#17
ReceiveCallback receiveMsgSize 17
[7984] Socket#31352595::BeginSend()
[7984] Exiting Socket#31352595::BeginSend() -> OverlappedAsyncResult#31071611
[22168] Data from Socket#31352595::PostCompletion
A first chance exception of type 'System.FormatException' occurred in Microsoft.VisualBasic.dll
[22168] 00000000 : 07 : . <-- RESULT RECEIVED, TEST2
[22168] Socket#31352595::EndSend(OverlappedAsyncResult#31071611)
[22168] Exiting Socket#31352595::EndSend() -> Int32#1
[22168] Socket#31352595::BeginReceive()
[22168] Exiting Socket#31352595::BeginReceive() -> OverlappedAsyncResult#51673536
SendCallBack 2 1
[4640] Data from Socket#31352595::PostCompletion
[4640] 00000000 : :
ReceiveCallback Exit 3
The thread '<No Name>' (0x4b1c) has exited with code 0 (0x0).
ReceiveCallback In 4
[4640] Socket#31352595::EndReceive(OverlappedAsyncResult#51673536)
[4640] Exiting Socket#31352595::EndReceive() -> Int32#0
ReceiveCallback Exit 4
[4640] Socket#37088038::Socket()
[4640] Exiting Socket#37088038::Socket()
AcceptCallback Start3
[4640] Socket#49538252::EndAccept(AcceptAsyncResult#39421196)
in connect WHILE 4
[17872] Socket#40528290::BeginAccept()
[17872] Exiting Socket#40528290::BeginAccept() -> AcceptAsyncResult#8948635
//ERROR THROWN HERE
AcceptCallback End 3
使用 netstat 进行监控
服务启动时出现这个，表示服务正在监听10002端口
TCP 0.0.0.0:10002 LON-WKS-ZER01:0 LISTENING
第一次和第二次扫描（即成功）一切正常。测试网络应用程序连接，发送“扫描文本”，各种回调委托被触发，我们得到了很好的回复。
Netstat 在第一次测试期间，在建立连接后：
TCP 0.0.0.0:10002 LON-WKS-ZER01:0 LISTENING
TCP 127.0.0.1:10002 apps:59574 ESTABLISHED
TCP 127.0.0.1:59574 apps:10002 ESTABLISHED
（然后扫描#1完成）
当调用 testApp mTCP.Close() 时，状态变为 CLOSE_WAIT 和 FIN_WAIT_2
TCP 0.0.0.0:10002 LON-WKS-ZER01:0 LISTENING
TCP 127.0.0.1:10002 apps:59574 CLOSE_WAIT
TCP 127.0.0.1:59574 apps:10002 FIN_WAIT_2
几分钟后，CLOSE 和 FIN 连接消失，但仍有 LISTENER
TCP 0.0.0.0:10002 LON-WKS-ZER01:0 LISTENING
接下来，发送scan#2，它重复上述序列，结果成功。
在第三次扫描中，当它尝试建立新连接时，该行的 AcceptCallback 中会抛出异常：
clntSock = servSock.ClntSock.EndAccept(asyncResult)
具体来说，它是一个 ArgumentException，“asyncResult 不是通过调用 BeginAccept 创建的”（请参阅 EndAccept）
因此，由于我无法理解的原因，第三次测试的 IASyncResult 导致 EndAccept 方法抛出 ArgumentException。
总结一下这个错误 - Connect 调用的 BeginAccept 为 AcceptCallback 设置了一个委托并传递了一个 IASyncResult。AcceptCallBacks EndAccept 引发 ArgumentException
我意识到做事情的方式不是很最新，我们最好用别的东西，但是一件事又另一件事（时间，资源）我需要尝试让轻微的适应工作。但我不明白为什么（现有客户端应用程序）连接、扫描、扫描、扫描、扫描等工作，但（网络应用程序）连接、扫描、断开连接、连接、扫描、断开连接在第三次扫描连接时失败
在此先感谢您的任何建议。