Sending file through TCP.... HELP !!!

[vignesh.a.p]

hello all and thank you in advance for any and all assistance

I'm working on a LAN file transfer application. I've established a TCP connection through TCP client and listener. I then used stream to send data. It worked fine for small files. But when I tried for larger files by sending chunks per instance it showed an exception error. I used timer to loop it. Here is the code...

Private Sub sendtimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sendtimer.Tick

        sendcount += 1



            If sendcount <= Math.Truncate(sendsize / 2048) Then '2048 buffer

                Dim filetonet(2047) As Byte
                sendfile.Read(filetonet, 0, 2048)
                sendstream.Write(filetonet, 0, 2048)
                
            ElseIf remain <> 0 Then

                Dim filetonet(remain - 1) As Byte
                sendfile.Read(filetonet, 0, filetonet.Length)
                sendstream.Write(filetonet, 0, filetonet.Length)


                'post send operations
               
                sendtimer.Enabled = False
                status.Text = "File Sent"
                sendfile.Close()
                sendstream.Dispose()
                sendclient.Close()

            Else

                'post send operations
                
                sendtimer.Enabled = False
                sendfile.Close()
                status.Text = "File Sent"
                sendstream.Dispose()
                sendclient.Close()

            End If

End Sub

The real problem is when this timer ticks for first time it sends 2048 bytes. But for second time the highlighted line produces cannot write error. Watch window shows that

my sendclient.connected = true for first time and second time its false.

why does it disconnect automatically? is there any other better way to do my transfer.. kindly help!

[i_am_newbie]

Try this...

[Al42]

I used timer to loop it.

That's your error. Send chunk N+1 after chunk N is sent. Using a timer you really have no idea what state the system is in when you send the next chunk. It may have been waiting a long time or, due to the path being slow, it may not even have started sending.

[vignesh.a.p]

The same error occurs when i use 'for' or 'while' loop... I'm new to VB... I could do only this far with my knowledge. Can anyone suggest a better way to do this transfer? Any suggestions regarding the class I should refer?

I got a doubt..... I'm reading data from a stream to a buffer. when i again repeat the same line of code, will the data from beginning of stream gets read again, or data after the last read position gets read?

[Al42]

That depends on the state of the stream, which is why you should let the state of the stream tell you when to read data. Or don't use a stream. What control are you using for your TCP connection? Winsock?