C# MAC Adresi Öğrenme "FormApplication"

using System.Management;
using System.Net.NetworkInformation;

public string MACAdresiAl()
        {
            NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
            String sMacAddress = string.Empty;
            foreach (NetworkInterface adapter in nics)
            {
                if (sMacAddress == String.Empty) sMacAddress = adapter.GetPhysicalAddress().ToString();
                textBox1.Text = (sMacAddress);
            }
            return sMacAddress;
            
        }

private void button1_Click(object sender, EventArgs e)
        {
            MACAdresiAl();
        }

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Management;
using System.Net.NetworkInformation;

namespace mac
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public string MACAdresiAl()
        {
            NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
            String sMacAddress = string.Empty;
            foreach (NetworkInterface adapter in nics)
            {
                if (sMacAddress == String.Empty) sMacAddress = adapter.GetPhysicalAddress().ToString();
                textBox1.Text = (sMacAddress);
            }
            return sMacAddress;
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MACAdresiAl();
        }

        
    }
}