private void button1_Click(object sender, EventArgs e)
 {
     if (openFileDialog1.ShowDialog() == DialogResult.OK)
     {
         string s = Class3.FileToString(openFileDialog1.FileName);
         GList  g = Class3.StrToMyList(s);
         textBox2.Text = s;
         openFileDialog1.Dispose();
     }
 }
        private void button3_Click(object sender, EventArgs e)
        {
            GList g = Class3.StrToMyList(textBox2.Text);
            int   k = Convert.ToInt32(textBox1.Text);

            if (g.FindNode(k))
            {
                g.Delete(k);
                if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    Class3.WriteToFileAll(saveFileDialog1.FileName, Class3.MyListToStr(g));
                }
            }
            else
            {
                MessageBox.Show("Такого элемента нет в списке");
            }
        }