how to use sockets and VB.net to send commands from a client to a server

'-------------------- server code ------------------------------
Imports System.Net.Sockets
Imports System.Text
Class TCPSrv
 
    Function Main()
        ' Must listen on correct port- must be same as port client wants to connect on.
 
        Const portNumber As Integer = 8000
        Dim tcpListener As New TcpListener(portNumber)
 
 
        tcpListener.Start()
        Debug.WriteLine("Waiting for connection...")
        Try
            'Accept the pending client connection and return 
            'a TcpClient initialized for communication. 
            Dim tcpClient As TcpClient = tcpListener.AcceptTcpClient()
            Debug.WriteLine("command sent.")
            ' Get the stream
            Dim networkStream As NetworkStream = tcpClient.GetStream()
            ' Read the stream into a byte array
            Dim bytes(tcpClient.ReceiveBufferSize) As Byte
            networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))
            ' Return the data received from the client to the console.
            Dim clientdata As String = Encoding.ASCII.GetString(bytes)
            MsgBox(clientdata)
            If clientdata.CompareTo("notepad") Then
 
                Shell("c:\windows\notepad.exe")
            End If
            Dim responseString As String = "Notepad started."
            Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes(responseString)
            networkStream.Write(sendBytes, 0, sendBytes.Length)
 
            'MsgBox("Message Sent /> : " + responseString)
            'Any communication with the remote client using the TcpClient can go here.
            'Close TcpListener and TcpClient.
            tcpClient.Close()
            tcpListener.Stop()
 
        Catch e As Exception
            MsgBox(e.ToString())
 
        End Try
 
    End Function
 
 
    Private Sub TCPSrv_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Shell("c:\windows\notepad.exe")
        Me.Show()
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnStartListen.Click
        My.Settings.StopClicked = False
        bnStartListen.Text = "Started"
        MsgBox("Server Started")
        Main()
    End Sub
 
    Private Sub bnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnStop.Click
        My.Settings.StopClicked = True
        Main()
    End Sub
End Class
 
'-----------------------------CLIENT CODE ----------------------------
Imports System.Net.Sockets
Imports System.Text
 
Public Class frmServerClient
 
    Private Sub frmServerClient_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.Show()
        'MsgBox("sending data")
    End Sub
 
    Function Main()
 
        Dim tcpClient As New System.Net.Sockets.TcpClient()
        tcpClient.Connect("127.0.0.1", 8000)
        Dim networkStream As NetworkStream = tcpClient.GetStream()
        If networkStream.CanWrite And networkStream.CanRead Then
            ' Do a simple write.
            Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes("notepad")
            networkStream.Write(sendBytes, 0, sendBytes.Length)
            ' Read the NetworkStream into a byte buffer.
            Dim bytes(tcpClient.ReceiveBufferSize) As Byte
            networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))
            ' Output the data received from the host to the console.
            Dim returndata As String = Encoding.ASCII.GetString(bytes)
            MsgBox("Host returned: " + returndata)
        Else
            If Not networkStream.CanRead Then
                MsgBox("cannot not write data to this stream")
                tcpClient.Close()
 
 
            Else
                If Not networkStream.CanWrite Then
                    MsgBox("cannot read data from this stream")
                    tcpClient.Close()
 
 
                End If
            End If
        End If
 
    End Function
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        MsgBox("sending data")
        Main()
    End Sub
End Class

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