Generate Random Number1

namespace RandomNoGenerate1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        
        private void btn_RGenerate_Click(object sender, EventArgs e)
        {
            Random rdm= new Random();
            textBox1.Text = rdm.Next(100, 1000).ToString();
            listBox1.Items.Add(textBox1.Text);
        }

        private void btn_Add_Click(object sender, EventArgs e)
        {
            //listBox1.Items.Add(textBox1.Text);
        }        
    }