C＃异步套接字文件传输

Question

嗯，我正在尝试编写一个C＃服务器应用程序，它将接收来自用C++编写的几个客户端的文件，主要问题是我对C＃.Net很新。

设法为同步套接字C＃服务器编写一个代码，但无法弄清楚如何为异步套接字字节明智地接收数据并将它们写入OnDataReceive回调中的单个文件。

public void OnDataReceived(IAsyncResult asyn) 
{ 
    try 
    { 
    SocketPacket socketData = (SocketPacket)asyn.AsyncState; 

    ////Original code inside this function 
    //int iRx = socketData.m_currentSocket.EndReceive(asyn); 
    //char[] chars = new char[iRx + 1]; 
    //System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder(); 
    //int charLen = d.GetChars(socketData.dataBuffer, 0, iRx, chars, 0); 
    //System.String szData = new System.String(chars); 
    //richTextBoxReceivedMsg.AppendText(szData); 

    ////My old code from Sync socket file transfer 
    //Receive data from client socket till it continues 
    byte[] bufferData = new byte[1024]; 
    int recvBytesLen = 0; 
    BinaryWriter bWrite = new BinaryWriter(File.Open(m_strCurrFolder + "File", FileMode.Append)); 
    do 
    { 
     recvBytesLen = clientSock.Receive(bufferData, bufferData.Length, 0); 
     bWrite.Write(bufferData, 0, recvBytesLen); 
    } while (recvBytesLen > 0); 

    //Closing file and socket once done 
    bWrite.Close(); 

    // Continue the waiting for data on the Socket 
    WaitForData(socketData.m_currentSocket); 
    } 
    catch (ObjectDisposedException) 
    { 
    System.Diagnostics.Debugger.Log(0, "1", "\nOnDataReceived: Socket has been closed\n"); 
    } 
    catch (SocketException se) 
    { 
    MessageBox.Show(se.Message); 
    } 
} 

Answer 1

找到这个链接是有帮助的，做我的工作。 https://code.msdn.microsoft.com/windowsapps/Fixed-size-large-file-dfc3f45d

private static void ReceiveCallback(IAsyncResult ar) 
{ 
    StateObject state = (StateObject)ar.AsyncState; 
    Socket clientSocket = state.WorkSocket; 
    BinaryWriter writer; 


    int bytesRead = clientSocket.EndReceive(ar); 
    if (bytesRead > 0) 
    { 
     //If the file doesn't exist, create a file with the filename got from server. If the file exists, append to the file. 
     if (!File.Exists(fileSavePath)) 
     { 
      writer = new BinaryWriter(File.Open(fileSavePath, FileMode.Create)); 
     } 
     else 
     { 
      writer = new BinaryWriter(File.Open(fileSavePath, FileMode.Append)); 
     } 


     writer.Write(state.Buffer, 0, bytesRead); 
     writer.Flush(); 
     writer.Close(); 


     // Notify the progressBar to change the position. 
     Client.BeginInvoke(new ProgressChangeHandler(Client.ProgressChanged)); 


     // Recursively receive the rest file. 
     try 
     { 
      clientSocket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); 
     } 
     catch 
     { 
      if (!clientSocket.Connected) 
      { 
       MessageBox.Show(Properties.Resources.DisconnectMsg); 
      } 
     } 
    } 
    else 
    { 
     // Signal if all the file received. 
     receiveDone.Set(); 
    } 
}