2 inputs from visual studio to arduino

Using Arduino Programming Questions
2

I posted this before but I thought I should post this again properly.

Someone please help me.

what I am trying to do:

  • have two outputs through Arduino (LCD, LED)

What I have:

  • using Visual Studio 2015, using C# right now

from visual studio, i have two buttons, and 1 text box (please see attachment for an image)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Arduino_Connection
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            serialPort1.Open();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            serialPort1.Write("A");
        }

        private void button2_Click(object sender, EventArgs e)
        {
            serialPort1.Write("j");
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}

I have not wrote down anything for the text box portion yet. Because i do not know if i can use same serialPort to send a data to Arduino when Arduino is reading from the same Serial

int data;

void setup() {
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}



void loop() 
{
  if (Serial.available())
  {
    data = Serial.read();

    if (data == 'A')
    {
      digitalWrite(13,HIGH);
    }
    else
    {
      digitalWrite(13,LOW);
    }
  }
 
}

so, basically i have the LED worked out. but if i were to have a text msg box work out using the visual studio with Arduino... how do i do that...?
Is there any way i can distinguish the data that i am trying to use from visual studio to arduino?

PLEASE HELP!!!

Thank you so much in advance!!

Capture.PNG