Use NetworkStream read and write : NetworkStream « Socket Network « VB.Net Tutorial

1. VB.Net Tutorial
2. Socket Network
3. NetworkStream

Imports System.Net.Sockets
Imports System.Net
Imports System.Threading
Imports System.Text

Public Class Tester
    
    Public Shared Sub Main
        Dim myTcpClient As New TcpClient()
        Dim myNetworkStream As NetworkStream

        Try
            myTcpClient.Connect("127.0.0.1", 12345)
            myNetworkStream = myTcpClient.GetStream()
        Catch ex As ArgumentOutOfRangeException
            Console.WriteLine(ex.Message)
        Catch ex As SocketException
            Console.WriteLine(ex.Message)
        End Try

        Dim myBytes() As Byte = Encoding.ASCII.GetBytes("asdf")

        myNetworkStream = myTcpClient.GetStream()
        myNetworkStream.Write(myBytes, 0, myBytes.Length)

        Dim bufferSize As Integer = myTcpClient.ReceiveBufferSize
        Dim myBufferBytes(bufferSize) As Byte

        myNetworkStream.Read(myBufferBytes, 0, bufferSize)
        Console.WriteLine(Encoding.ASCII.GetString(myBufferBytes, 0, bufferSize))
    End Sub
End Class

No connection could be made because the target machine actively refused it

Unhandled Exception: System.InvalidOperationException: The operation is not allowed on non-connected
 sockets.
   at System.Net.Sockets.TcpClient.GetStream()
   at Tester.Main()