How to close Form2 via Form1 from another C# thread?

Question

C++ / C#

Through Form1 I launch Form2 with ProgressBar:

private void Button1_Click(object sender, EventArgs e)
        {
          if (backgroundWorker1.IsBusy != true)
            {
                frm2 = new Form2();
                frm2.Canceled += new EventHandler<EventArgs>(buttonCancel_Click);
                frm2.Show();
                backgroundWorker1.RunWorkerAsync();
            }
        }

If ts.Connect() returns false, then close Form2:

//делает трудоемкую работу

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            worker = sender as BackgroundWorker;
            //проверяем не запрошено-ли отмена фоновой операции
            if (worker.CancellationPending == true)
            {
                e.Cancel = true;
            }
            else
            {
                // Выполняем трудоемкую операцию 

                Tcp_Socket ts = new Tcp_Socket();
                bool ab=ts.Connect();
                if (ab == false)
                {
                    e.Cancel = true;
                      // Отмена асинхронной операции.
                backgroundWorker1.CancelAsync();

                // Закрываем Form2
               frm2.Close();
                    
                }

             
            }

        }

Throws an error on frm2.Close()
Illegal multi-thread operation: Attempt to access control 'Form2' from a thread other than the thread it was created on."
Please help! How to close Form2 from Form1 from another thread. Maybe with delegates somehow possible?

Answer 1

Read here