Liste

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 WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        List<int> database = new List<int>();
        public Form1()
        {
            InitializeComponent();
        }

        private void btnIndsæt_Click(object sender, EventArgs e)
        {
            database.Add(int.Parse(txtInout.Text));
        }

        private void btnRemove_Click(object sender, EventArgs e)
        {
            database.Remove(int.Parse(txtInout.Text));
        }

        private void btnSort_Click(object sender, EventArgs e)
        {
            database.Sort();
        }

        private void btnUd_Click(object sender, EventArgs e)
        {
            foreach (int item in database)
            {
                lstUd.Items.Add(item);
            }
        }

        private void btnSum_Click(object sender, EventArgs e)
        {
            int sum = 0;
            foreach (int item in database)
            {
                sum = sum + item;
            }
            lblSum.Text = sum.ToString();
        }
    }
}