0101_1/WpfApp1/MainWindow.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.Navigation;
using System.Windows.Shapes;
using System.IO;
using static System.Net.Mime.MediaTypeNames;

namespace WpfApp1
{
    /// <summary>
    /// Логика взаимодействия для MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        string pant = "1.txt";
        public MainWindow()
        {
            InitializeComponent();
        }

        struct people
        {
            public string name;
            public string dateB;
            public string pol;
            public string di;
        }

        List<people> peopleList = new List<people>();
        int n = 1;
        bool flag = false;
        int count = 0;
        string zapis()
        {            
            string text = "";
            text += tb_name + " ";
            text += dp_date + " ";
            
            if (lb_pol.SelectedItem is per person)
            {
                text += person.pol + " ";
                //MessageBox.Show(person.pol);
            }
            if(cb_1.IsChecked == true) 
            {
                text += cb_1.Content;
            }
            if(cb_2.IsChecked == true) 
            {
                text += cb_2.Content;
            }
            if(cb_3.IsChecked == true) 
            {
                text += cb_3.Content;
            }
            return text;
        }

        void initialDate(int n)
        {
            using (StreamReader sr = new StreamReader(pant))
            {
                try 
                {
                if (flag == true)
                {
                    for (int i = 0; i < count; i++)
                    {
                        sr.ReadLine();
                    }
                }
                string[] pl = sr.ReadLine().Split(' ');
                people peoples = new people();
                peoples.name = (pl[n]);
                peoples.dateB = pl[n + 1];
                peoples.pol = pl[n + 3];
                peoples.di = pl[n + 4];
                peopleList.Add(peoples); 
                }
                catch  
                {
                    MessageBox.Show("больше данных нет");
                }
            }
            
        }

        void show() 
        {
            initialDate(n);
            foreach (people people in peopleList) 
            {
                nameV.Content = Convert.ToString(people.name);
                datenV.Content = Convert.ToString(people.dateB);
                polV.Content = Convert.ToString(people.pol);
                diV.Content = Convert.ToString(people.di);
            }
            
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            File.AppendAllText(pant, zapis() + Environment.NewLine);
         
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {            
            show();
            flag = true;
        }

        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            if (flag==true)
            {
                count++;
                show();
            }
        }
    }
}