Error message TCPClient

Hi

I am creating an web application that connects to an tcp server.

When i give the command to connect to the server, he gives an response from the server and an textbox and Commandbutton are visible for command`s to the server.

When i am sending an command to the server then i get this error:

"The operation is not allowed on non-connected sockets."

This is my full cource:

Imports System.Net.Sockets

Class _Default
Inherits System.Web.UI.Page
Public client As New System.Net.Sockets.TcpClient()
Public NetworkStream As NetworkStream
Public bytes(client.ReceiveBufferSize) As Byte
Public returndata As String
Public SendBytes As Byte()

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
On Error GoTo fout
client.Connect("207.42.200.123", 81)
Label1.Text = "Connected to server"
Label1.ForeColor = Drawing.Color.Black
TextBox1.Visible = True
txt_send.Visible = True
cmd_send.Visible = True
NetworkStream = client.GetStream()
NetworkStream.Read(bytes, 0, CInt(client.ReceiveBufferSize))
returndata = Encoding.ASCII.GetString(bytes)
TextBox1.Text = returndata
Exit Sub
fout:
Button2.Visible = False
Label1.Text = "Error when trying to connect to server"
Label1.ForeColor = Drawing.Color.Red

End Sub

Protected Sub cmd_send_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmd_send.Click
SendBytes = Encoding.ASCII.GetBytes(txt_send.Text)
NetworkStream = client.GetStream()
NetworkStream.Write(SendBytes, 0, SendBytes.Length)
NetworkStream = client.GetStream()
NetworkStream.Read(bytes, 0, CInt(client.ReceiveBufferSize))
returndata = Encoding.ASCII.GetString(bytes)
TextBox1.Text = TextBox1.Text & vbCrLf & returndata
End Sub

Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
TextBox1.Visible = False
txt_send.Visible = False
cmd_send.Visible = False
client.Close()
End Sub
End Class

The error is in line 37 :

Line 35: Protected Sub cmd_send_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmd_send.Click
Line 36: SendBytes = Encoding.ASCII.GetBytes(txt_send.Text)
Line 37: NetworkStream = client.GetStream()
Line 38: NetworkStream.Write(SendBytes, 0, SendBytes.Length)
Line 39: NetworkStream = client.GetStream()

Can somebody help me

Answer this question

Error message TCPClient

Scott Currie MSFT
Can you make an example for me so it will work

Thnx
jlkirkjr
Isn't that a different question

In your code, the NetworkStream variable gets set in the code run by the connect button1. You have to run that before you run the code in the send button, or you will get the error you posted.

Tracy
sanjay_shinder
The server request autorisation.
so i need a way that the connection always stays open on an session.

if you know what i mean

DexterDurai

When is remove that line i will get this error:

Object reference not set to an instance of an object.

Line 36: SendBytes = Encoding.ASCII.GetBytes(txt_send.Text)
Line 37: 'NetworkStream = client.GetStream()
Line 38: NetworkStream.Write(SendBytes, 0, SendBytes.Length)
Line 39: NetworkStream = client.GetStream()
Line 40: NetworkStream.Read(bytes, 0, CInt(client.ReceiveBufferSize))

wizArdcn

There is no need to get the NetworkStream a second time in the cmd_send_Click().
You can use the network stream that you got originally to read and write.
The fact that a network stream is already opened on the tcpclient is the issue.
Granted we could have thrown a better exception, please fix your code and see if the problem goes away
Will Merydith
The example you posted should work if you are sure to run the connect code before you run the send code.
Tracy
acgentry
Are you sure you are always running the connect code before the send code
Tracy
Error message TCPClient

Answer this question