private void Form1_FormClosing(object sender, System.ComponentModel.CancelEventArgs e)// chiusura
    {   
      DialogResult result =MessageBox.Show("Sì -> Chiude l'applicazione" +  "\r\nNo -> Riduce nella traybar","", MessageBoxButtons.YesNo);

      if (result == DialogResult.No)
      {
        e.Cancel = true;
        notifyIcon1.Visible = true;
        //this.Hide();
        this.ShowInTaskbar = false;
        this.Visible = false;
        //this.Activate();
      }
    }








private void notifyIcon1_DoubleClick(object Sender, EventArgs e) 
    {
      if (this.WindowState == FormWindowState.Minimized)
      {
          this.WindowState = FormWindowState.Normal;
              this.ShowInTaskbar = true; 
        notifyIcon1.Visible = false;
      }   
      // Activate the form.
      this.Activate();
    }