在命名管道上從visual basic .net 2010調用WriteFile的錯誤

Question

我一整天都在關注這個問題，並且我無法理解關於此的各種（有時是衝突的）文檔。爲了增加混淆，在白天的某個時候，這確實（有點）工作 - 即沒有發出訪問違規錯誤。但是管道另一端的數據是無稽之談，所以我懷疑這只是偶然發生的。

我有一個vb.net程序（使用.net 3.0所以不支持System.IO.NamedPipes :(）它創建一個命名管道，並等待另一個應用程序來連接和發送一些數據作爲'ack' ，然後我想讓vb程序發送收到的消息的總長度，我可以創建管道，等待連接並接收消息，但是它會嘗試使用WriteFile發送'ack'。我使用WriteFile（當前）的定義是基於相應ReadFile，這似乎很好地工作：

Declare Function ReadFile Lib "kernel32" (_ 
    ByVal hFile As Integer, _ 
    ByRef lpBuffer As Byte, _ 
    ByVal nNumberOfBytesToRead As Integer, _ 
    ByRef lpNumberOfBytesRead As Integer, _ 
    ByVal lpOverlapped As Integer) _ 
    As Integer 

Declare Function WriteFile Lib "kernel32" (_ 
    ByVal hFile As Long, _ 
    ByRef lpBuffer As Byte, _ 
    ByVal nNumberOfBytesToWrite As Integer, _ 
    ByRef lpNumberOfBytesWritten As Integer, _ 
    ByVal lpOverlapped As Integer) _ 
    As Integer 

的精簡代碼（錯誤檢查和調試印刷去除）看起來像這樣：

Dim openMode = PIPE_ACCESS_DUPLEX Or FILE_FLAG_FIRST_PIPE_INSTANCE 
Dim pipeMode = PIPE_WAIT Or PIPE_TYPE_MESSAGE Or PIPE_READMODE_MESSAGE 
Dim res ' Result of dll calls 

pipeN2Q = CreateNamedPipe("\\.\pipe\N2Q", openMode, pipeMode, 10, 1024, 1024, 2000, IntPtr.Zero) 
res = ConnectNamedPipe(pipeN2Q, 0) 

Dim rxCount As Integer = 0 ' To hold the number of bytes received 
Dim txCount As Integer = 0 ' To hold the number of bytes sent 
Dim txReq As Integer = 2 ' To hold the number of bytes we're going to ask to be sent during the 'ack' 

Dim dataIn(256) As Byte 

res = ReadFile(pipeN2Q, dataIn(0), 256, rxCount, Nothing) 

Dim recvBuffer As String = System.Text.Encoding.ASCII.GetString(dataIn, 0, rxCount) 

Dim dataOut(2) As Byte 
dataOut(0) = 42 
dataOut(1) = 43 

res = WriteFile(pipeN2Q, dataOut(0), txReq, txCount, Nothing) 

一旦代碼獲取到WriteFile，它拋出一個AccessViolationException - 「嘗試讀取或寫入受保護的內存。」我猜想這是抱怨dataOut參數，但它沒有給出進一步的細節。事情到目前爲止，我已經試過包括：

• 改變的WriteFile的聲明，使lpBuffer聲明：使用Marshal.AllocHGlobal(txReq)ByVal lpBuffer as IntPtr
• 清分數據出，並使用Marshal.WriteInt16()
• 分配的dataOut大的緩衝初始化（1024個字節）並將它們初始化爲零

要清楚，來自其他應用程序的消息可以完美接收，並且recvBuffer與發送的字符串完全相同。我無法說服WriteFile進行合作（除了一次，也許偶然，我無法重複）。我希望這只是變量的聲明或初始化 - 任何線索？

Answer 1

根據Hans的建議使用pinvoke.net，這裏是最終爲我工作的簽名和調用的組合 - 以防萬一任何人都可以使用它。我知道我可能應該將這些前3個聲明轉換爲與ReadFile/WriteFile相同的格式，但現在它的工作原理是...

Declare Function CreateNamedPipe Lib "kernel32" Alias "CreateNamedPipeA" (_ 
    ByVal lpName As String, ByVal dwOpenMode As Integer, _ 
    ByVal dwPipeMode As Integer, ByVal nMaxInstances As Integer, _ 
    ByVal nOutBufferSize As Integer, ByVal nInBufferSize As Integer, _ 
    ByVal nDefaultTimeOut As Integer, ByVal lpSecurityAttributes As IntPtr) _ 
    As SafeFileHandle 

Declare Function ConnectNamedPipe Lib "kernel32" (_ 
    ByVal hNamedPipe As SafeFileHandle, ByVal lpOverlapped As System.Threading.NativeOverlapped) _ 
    As SafeFileHandle 

Declare Function CloseHandle Lib "kernel32" (_ 
    ByVal hFile As SafeFileHandle) _ 
    As Integer 

<DllImport("kernel32.dll", SetlastError:=True)> Friend Shared Function WriteFile(_ 
ByVal File As SafeFileHandle, _ 
ByVal Buffer As System.Text.StringBuilder, _ 
ByVal NumberOfBytesToWrite As Integer, _ 
ByRef NumberOfBytesWritten As Integer, _ 
ByRef Overlapped As System.Threading.NativeOverlapped) As <MarshalAs(UnmanagedType.Bool)> Boolean 
End Function 

<DllImport("kernel32.dll")> Friend Shared Function ReadFile(_ 
ByVal File As SafeFileHandle, _ 
ByVal Buffer As System.Text.StringBuilder, _ 
ByVal NumberOfBytesToRead As Integer, _ 
ByRef NumberOfBytesRead As Integer, _ 
ByRef Overlapped As System.Threading.NativeOverlapped) As <MarshalAs(UnmanagedType.Bool)> Boolean 
End Function 

... 

pipeN2Q = CreateNamedPipe("\\.\pipe\N2Q", openMode, pipeMode, 10, 1024, 1024, 2000, IntPtr.Zero) 
If Not pipeN2Q.IsInvalid Then 
    If Not ConnectNamedPipe(pipeN2Q, Nothing).IsInvalid Then 

     Dim rxCount As Integer = 0 
     Dim txCount As Integer = 0 

     Dim dataIn As New System.Text.StringBuilder 

     res = ReadFile(pipeN2Q, dataIn, 256, rxCount, Nothing) 
     If res <> 0 Then 
      Dim dataOut As New StringBuilder(dataIn.Length.ToString) 

      res = WriteFile(pipeN2Q, dataOut, dataOut.Length, txCount, Nothing) 
     Else 
      Debug.Print("ReadFile ERROR: " & Err.LastDllError) 
     End If 
    Else 
     Debug.Print("ConnectNamedPipe ERROR: " & Err.LastDllError) 
    End If 
    If CloseHandle(pipeN2Q) <> 0 Then 
     Debug.Print("Pipe closed") 
    Else 
     Debug.Print("CloseHandle ERRPR: " & Err.LastDllError) 
    End If 
Else 
    Debug.Print("CreateNamedPipe ERROR: " & Err.LastDllError) 
End If