1 using System; 2 using System.Collections.Generic; 3 using System.ComponentModel; 4 using System.Data; 5 using System.Drawing; 6 using System.Linq; 7 using System.Text; 8 using System.Threading.Tasks; 9 using System.Windows.Forms;10 11 namespace WindowsFormsApplication112 {13     public partial class Form1 : Form14     {15         public Form1()16         {17             InitializeComponent();18         }19 20         private void button1_Click(object sender, EventArgs e)21         {22             treeView1.Nodes.Add(textBox2.Text);23         }24     }25 }