Label, TextBox og ListBox

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 WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnOpdater_Click(object sender, EventArgs e)
        {
            string temp = txtInput.Text;

            lblUd.Text = lblUd.Text + temp;
            txtUd.Text = txtUd.Text + temp;
            lstUd.Items.Add(temp);
        }
    }
}