i Need To Use If COndition when serial port get value from Arduino

Hello Every One

im trying to use if condition in vb when serial port read from arduino
so i wana when i get value like "A" in textbox do action and not working !! i receive value but if condition not become true idont know why so can anyone can help me !!

arduino code :

char data;
int A = 13;
int B = 12;
int C = 11;
int D = 10;


void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(A,OUTPUT);
pinMode(B,OUTPUT);
pinMode(C,OUTPUT);
pinMode(D,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
while (Serial.available()>0){
  data=Serial.read();
  if (data == 'z'){
      digitalWrite (13,HIGH);
      Serial.println("A");}
      
   if (data == 'x'){
      digitalWrite (13,LOW);
      Serial.println("A OFF");}
   
     if (data == 'c'){
      digitalWrite (12,HIGH);
      Serial.println("B ON");}
     
 if (data == 'v'){
      digitalWrite (12,LOW);
      Serial.println("B OFF");}

    if (data == 'b'){
      digitalWrite (11,HIGH);
      Serial.println("C ON");}

   if (data == 'n'){
      digitalWrite (11,LOW);
      Serial.println("C OFF");}

    if (data == 'm'){
      digitalWrite (10,HIGH);
      Serial.println("D ON");}

   if (data == 'l'){
      digitalWrite (10,LOW);
      Serial.println("D OFF");}
} }

VB Code :

Imports System.IO.Ports

Public Class Form1

    Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        Dim Sdata As String = SerialPort1.ReadLine()
        TextBox2.Clear()
        TextBox2.Text = Sdata
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Windows.Forms.Control.CheckForIllegalCrossThreadCalls = False
        SerialPort1.Open()
        Timer1.Start()

    End Sub

    Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
        If e.KeyCode = Keys.Enter Then
            SerialPort1.Write(TextBox1.Text)
            TextBox1.Clear()
        End If
    End Sub

End Class

Please Only i need if condition when serial port get value from arduino and make it true

This sounds like a question for a VB forum ?

...R

Robin2:
This sounds like a question for a VB forum ?

...R

Right ! VB