Чем заменить можно arg[0] в примере

using System;
using System.Net;
using System.Net.NetworkInformation;
using System.Text;
 
namespace Examples.System.Net.NetworkInformation.PingTest
{
    public class PingExample
    {
        // args[0] can be an IPaddress or host name.
        public static void Main (string[] args)
        {
            Ping pingSender = new Ping ();
            PingOptions options = new PingOptions ();
 
            // Use the default Ttl value which is 128,
            // but change the fragmentation behavior.
            options.DontFragment = true;
 
            // Create a buffer of 32 bytes of data to be transmitted.
            string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
            byte[] buffer = Encoding.ASCII.GetBytes (data);
            int timeout = 120;
            PingReply reply = pingSender.Send (args[0], timeout, buffer, options);
            if (reply.Status == IPStatus.Success)
            {
                Console.WriteLine ("Address: {0}", reply.Address.ToString ());
                Console.WriteLine ("RoundTrip time: {0}", reply.RoundtripTime);
                Console.WriteLine ("Time to live: {0}", reply.Options.Ttl);
                Console.WriteLine ("Don't fragment: {0}", reply.Options.DontFragment);
                Console.WriteLine ("Buffer size: {0}", reply.Buffer.Length);
            }
        }
    }
}

  PingReply reply = pingSender.Send (args[0], timeout, buffer, options);

PingReply reply = pingSender.Send ("localhost", timeout, buffer, options);

PingReply reply = pingSender.Send (textBox1.Text, timeout, buffer, options);

    static class Program
    {
        /// <summary>
        /// Главная точка входа для приложения.
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1(args));
        }
    }

    public partial class Form1 : Form
    {
        private string[] args;
 
        public Form1()
        {
            InitializeComponent();
        }
 
        public Form1(string[] args)
            : this()
        {
            this.args = args;
        }
    }