Visual Basic TcpClient + Arduino

Imports System.Net.Sockets
Public Class Form1

    Private Delegate Sub AppendTextBoxDelegate(ByVal TB As RichTextBox, ByVal txt As String)

    Private Sub AppendTextBoxes(ByVal TB As RichTextBox, ByVal txt As String)
        If TB.InvokeRequired Then
            TB.Invoke(New AppendTextBoxDelegate(AddressOf AppendTextBoxes), New Object() {TB, txt})
        Else
            TB.Text += ""
            TB.Text = RichTextBox1.Text + Environment.NewLine + " >> " + txt
        End If
    End Sub

    Dim clientSocket As New System.Net.Sockets.TcpClient()
    Dim serverStream As NetworkStream
    Dim data As [Byte]()

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Start Butonu
        If Not BackgroundWorker1.IsBusy Then
            BackgroundWorker1.RunWorkerAsync()
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AppendTextBoxes(RichTextBox1, "Client Started")
        'BackgroundWorker1.RunWorkerAsync()
    End Sub

    Private Sub My_BgWorker_DoWork1(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork

        Try
            clientSocket.Connect("192.168.2.195", 4545)
            AppendTextBoxes(RichTextBox1, "Client Socket Program - Server Connected ...")

            Dim serverStream As NetworkStream = clientSocket.GetStream()

            If serverStream.CanRead = True Then
                Do
                    Dim inStream As [Byte]() = New [Byte](256) {}
                    Dim bytes As Int32 = serverStream.Read(inStream, 0, inStream.Length)
                    Dim returndata As String = System.Text.Encoding.ASCII.GetString(inStream, 0, bytes)
                    AppendTextBoxes(RichTextBox1, "Data from Server : " + returndata)
                    Console.WriteLine("Data from Server : " + returndata)
                Loop Until serverStream.CanRead = False
            Else
                AppendTextBoxes(RichTextBox1, "No Data to Receive")
                clientSocket.Close()
                serverStream.Close()
            End If
        Catch ex As Exception
            MessageBox.Show(Environment.NewLine & ex.Message & Environment.NewLine & ex.StackTrace, "Dumping To Log", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
        End Try
    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        If e.Cancelled Then
            MsgBox("Cancelled")
        End If
        AppendTextBoxes(RichTextBox1, "Finished Getting Stream!")
    End Sub

    Private Sub RichTextBox1_TextChanged(sender As Object, e As EventArgs) Handles RichTextBox1.TextChanged
        RichTextBox1.SelectionStart = RichTextBox1.Text.Length
        RichTextBox1.ScrollToCaret()
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

        clientSocket.GetStream().Close()
        clientSocket.Close()

        If Not BackgroundWorker1.IsBusy Then
            BackgroundWorker1.CancelAsync()
        End If
    End Sub
End Class

#include <SPI.h>
#include <Ethernet.h>
#include <MFRC522.h>

#define SS_PIN 8
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance.

int readsuccess;
byte readcard[4];
char str[32] = "";
String StrUID;


// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};

IPAddress ip(192, 168, 2, 195);
IPAddress gateway(192, 168, 2, 1);
IPAddress subnet(255, 255, 255, 0);
IPAddress primaryDNS(192, 168, 2, 1);

EthernetServer server(4545);
bool alreadyConnected = false; // whether or not the client was connected previously


void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  // You can use Ethernet.init(pin) to configure the CS pin
  Ethernet.init(10);  // Most Arduino shields
 
  SPI.begin();      // Init SPI bus
  mfrc522.PCD_Init(); // Init MFRC522 card

  // initialize the Ethernet device not using DHCP:
  Ethernet.begin(mac, ip, gateway, primaryDNS, subnet);

  // print your local IP address:
  Serial.print("My IP address: ");
  Serial.println(Ethernet.localIP());

  // start listening for clients
  server.begin();

}

void loop() {
  EthernetClient client = server.available();

  readsuccess = getid();
 
  if(readsuccess){
    server.write(StrUID.c_str());
    Serial.println(StrUID);
    delay(1000);
  }

Ethernet.maintain();
}


// --------------------------------------------------------------------
int getid() {
  if (!mfrc522.PICC_IsNewCardPresent()) {
    return 0;
  }
  if (!mfrc522.PICC_ReadCardSerial()) {
    return 0;
  }
  for (int i = 0; i < 4; i++) {
    readcard[i] = mfrc522.uid.uidByte[i]; //storing the UID of the tag in readcard
    array_to_string(readcard, 4, str);
    StrUID = str;
  }
  mfrc522.PICC_HaltA();
  return 1;
}
// --------------------------------------------------------------------
void array_to_string(byte array[], unsigned int len, char buffer[])
{
  for (unsigned int i = 0; i < len; i++)
  {
    byte nib1 = (array[i] >> 4) & 0x0F;
    byte nib2 = (array[i] >> 0) & 0x0F;
    buffer[i * 2 + 0] = nib1  < 0xA ? '0' + nib1  : 'A' + nib1  - 0xA;
    buffer[i * 2 + 1] = nib2  < 0xA ? '0' + nib2  : 'A' + nib2  - 0xA;
  }
  buffer[len * 2] = '\0';
}