[Mono-list] C#/Mono Serial port communication

[Jon-Eirik Pettersen]

Gonzalo Paniagua Javier wrote:
> On Wed, 2004-11-24 at 22:22 +0100, Jon-Eirik Pettersen wrote:
> 
>>I don't think I have enough information to do it.
>>
>>It says the stream is seek-able because it thinks it is a normal file it 
>>is opening, but seeking do not seems to work on devices.
> 
> 
> The bug is exactly that. The runtime should figure out whether the file
> is seekable or not.
> 
> 
>>But if I send the data  directly to the FileStream using the 
>>Write-function it works, but I have problems reading the data from the 
>>stream.
> 
> 
> Try using the stream in the file attached.
> 
> -Gonzalo
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> using System.IO;
> 
> class NoSeekStream : FileStream {
> 	public NoSeekStream (string name, FileMode mode, FileAccess access)
> 		: base (name, mode, access)
> 	{
> 	}
> 
> 	public override bool CanSeek {
> 		get { return false; }
> 	}
> }
> 

I have made a buggy application that is able to send data (if I send 
ATZxxxxxxxx I can see in the other end that it works), but it is not 
able to receive data:

using System;
using System.Text;
using System.IO;
using System.Threading;
using System.Collections;

namespace serialchattest {
   class serialchattest {
     static string device = "/dev/rfcomm0";
     static ArrayList rbuf = new ArrayList();
     static FileStream fs = null;
     static StreamReader sr = null;

     static void SendCommand(string cmd) {
       try {
         string data = cmd + "\r\n";
         byte[] bt = Encoding.UTF8.GetBytes(data);
         fs.Write(bt, (int) fs.Position, bt.Length);
         sr.ReadLine();
       } catch (Exception) {} finally {}
     }

     static void ReadResponse() {
       string data = null;
       while ((data = sr.ReadLine()) != null) {
         rbuf.Add(data);
       }
     }

     static string GetResponse() {
       try {
         if (rbuf.Count > 0) {
           string ret = (string) rbuf[0];
           rbuf.RemoveAt(0);
           return ret;
         } else {
           return null;
         }
       } catch (Exception) { return null; } finally {}
     }

     static void Main() {
       fs = new FileStream(device, FileMode.Open, FileAccess.ReadWrite, 
0, 1024, true);
       sr = new StreamReader(fs);
       SendCommand("AT");
       string res = null;
       ReadResponse();
       while ((res = GetResponse()) != null) {
         Console.WriteLine(res);
       }
     }
   }
}

The result is:


Unhandled Exception: System.NullReferenceException: Object reference not 
set to an instance of an object

Unhandled Exception: System.NullReferenceException: Object reference not 
set to an instance of an object

Unhandled Exception: System.NullReferenceException: Object reference not 
set to an instance of an object

Unhandled Exception: System.NullReferenceException: Object reference not 
set to an instance of an object