docs-desktop/dotnet-desktop-guide/net/wpf/get-started/snippets/create-app-visual-studio/csharp/Final.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace Names
{
    /// <summary>
    /// Interaction logic for Final.xaml
    /// </summary>
    public partial class Final : Window
    {
        public Final()
        {
            InitializeComponent();
        }

        //<FinalCode>
        private void ButtonAddName_Click(object sender, RoutedEventArgs e)
        {
            if (!string.IsNullOrWhiteSpace(txtName.Text) && !lstNames.Items.Contains(txtName.Text))
            {
                lstNames.Items.Add(txtName.Text);
                txtName.Clear();
            }
        }
        //</FinalCode>
    }
}