Wierd Results with non textual data

[Nate Bross]

Hi Guys:

 

I have an interesting delima. I am trying to send data over a network, the data I am sending contains UNICODE values, but the recieving end needs to get the ASCII value of each byte.

 

I have a server and client. The client sends data to the server and when it gets there it comes out as "?" question marks.

 

Server Recieval Code:

Dim networkStream As NetworkStream = objTCPClient.GetStream()

           ' Read the stream into a byte array
           Dim bytes(objTCPClient.ReceiveBufferSize) As Byte
           networkStream.Read(bytes, 0, CInt(objTCPClient.ReceiveBufferSize))

           ' Return the data received from the client to the console.
           Dim ClientData As String = Encoding.ASCII.GetString(bytes)
           'Call OwningForm.DebugText(("Client " & sKey & "> " & ClientData))
           Call OwningForm.ProcessIncomingTCP(ClientData, sKey)


           Dim responseString As String = "Recieved."
           Dim sendBytes As [byte]() = Encoding.ASCII.GetBytes(responseString)
           networkStream.Write(sendBytes, 0, sendBytes.Length)
           'Call OwningForm.DebugText(("Server Sent> " & responseString))

 

Client Code:

Message = "BIN@þ"

       Try
           ' Create a TcpClient.
           ' Note, for this client to work you need to have a TcpServer 
           ' connected to the same address as specified by the server, port
           ' combination.
           Dim port As Int32 = 222
           Dim client As New TcpClient("192.168.1.111", port)

           ' Translate the passed message into ASCII and store it as a Byte array.
           Dim data() As Byte = System.Text.Encoding.Unicode.GetBytes(Message)

           ' Get a client stream for reading and writing.
           '  Stream stream = client.GetStream();
           Dim stream As NetworkStream = client.GetStream()

           ' Send the message to the connected TcpServer. 
           stream.Write(data, 0, data.Length)

           Console.WriteLine("Sent: {0}", Message)

           ' Receive the TcpServer.response.
           ' Buffer to store the response bytes.
           data = New [byte](256) {}

           ' String to store the response ASCII representation.
           Dim responseData As [string] = [string].Empty


           ' Do Until False
           ' Read the first batch of the TcpServer response bytes.
           Dim bytes As Int32 = stream.Read(data, 0, data.Length)
           responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes)
           Console.WriteLine("Received: {0}", responseData)
           Application.DoEvents() 'let windows think
           'Loop

           ' Close everything.
           client.Close()
       Catch ex As ArgumentNullException
           Console.WriteLine("ArgumentNullException: {0}", ex)
       Catch ex As SocketException
           Console.WriteLine("SocketException: {0}", ex)
       End Try

       Console.WriteLine(ControlChars.Cr + " Press Enter to continue...")
       Console.Read()

 

As you can see, the right three characters is the important data; however, when I recieve it it comes over as "?" question marks.

 

The actual ASCII values of the three bytes are 254, 18, and 28 respectively.

 

Any and all advice is appreciated.

[PlausiblyDamp]

In your code you have the lines

' Translate the passed message into ASCII and store it as a Byte array.
Dim data() As Byte = System.Text.Encoding.Unicode.GetBytes(Message)

did you mean to use Unicode there?

 

Would it be posible to attach the code for the client and server its (or a simple stripped down version of them)?

[Nate Bross]

Yeah, I uploaded the code for both client and server. The basic idea is the 'server' is going to recieve data from network clients, and spit it out to a third party device through the serial port. Thanks for your help.

ClientServer.zip

Edited June 23, 2005 by PlausiblyDamp

[PlausiblyDamp]

Will have a better look at it later today - but as a quick one is the mscomm control required for the server as I can't see any code that refers to a serial port in there.

 

Quick update:

In your server try using

' Return the data received from the client to the console.
Dim ClientData As String
ClientData = Encoding.ASCII.GetString(Encoding.ASCII.Convert(Encoding.Unicode, Encoding.ASCII, bytes))

in place of your existing

' Return the data received from the client to the console.
Dim ClientData As String = Encoding.ASCII.GetString(bytes)

Edited June 23, 2005 by PlausiblyDamp

[Nate Bross]

Okay that worked except the first byte chr(254) is showing up as question mark "?" on the server side. When properly displayed in a text box it should be displayed as "þ".

 

In the client replace the line:

Message = "BIN@þ"

With:

Message = "BIN@" & Chr(254) & Chr(18) & Chr(28)

That string works if run directly from the server to the rs232. Like I said, the chr(254) displays as a chr(63) "?" after being sent.

[PlausiblyDamp]

Not all ANSI / UNICODE characters have an equivalent ASCII character. ASCII only defines the code up to 127 so anything beyond that isn't going to work anyway.

[Nate Bross]

Is there a way I can send binary data? I know ASCII only uses seven bytes, I need to use the eighth byte. I didn't have any trouble sending data via Winsock in vb 6 to the .net server. My issue is converting the string to a byte array.

[PlausiblyDamp]

If you need to send binary data then don't convert it to a text based format both the .Read and .Write methods of a stream accept binary data.

[Nate Bross]

Issue resolved!

 

Resolution:

 

Changed Existing VB code:

System.Text.Encoding.ASCII.GetBytes(Message)

To the Following VB Code:

System.Text.Encoding.UTF8.GetBytes(Message)

 

Thanks for your help on this issue PlausiblyDamp, I really appreciate it.