c#截取文件路径

  private void button1_Click(object sender, EventArgs e)
        {
        
             string s=textBox1.Text.Trim();
             int idex = s.IndexOf("\\");           
           while (s.IndexOf("\\")!=-1)
             {
                 textBox2.AppendText(s.Substring(0, s.IndexOf("\\")));
                 s = s.Substring(s.IndexOf("\\") + 1);
             }
                        
            textBox2.AppendText(s);
        }