//FORM OBJECT

    public partial class Form1 : Form    {
        Progress prog;


...
        //transfer data only
        private void button4_Click(object sender, EventArgs e) {
            prog = new Progress();
            foreach (Object o in checkedListBox1.CheckedItems) {
                Device d = (Device)o;
                if (!d.isEmpty) {
                    toolStripStatusLabel1.Text = "Processing " + d.Name;
                    prog.add( d.Name );
                    Thread t = new Thread((ParameterizedThreadStart) d.transfer);
                    t.Start(this);
                }
            }
            prog.show();
        }


....
/// IN Device Object

        public void transfer(Object x) {

            ....

            transferFile(timestamp, 0, dataEnd, target, false, (Form1) x);
        }



      public void transferFile(DateTime t, long startPage, long endPage, String target, bool wipe, Form1 form) {
    .........

        if (page > (oldPage + pageInc) {
                    oldPage = page;

            THE INVOKER CODE SHOULD GO HERE

    ----> I want this to happen -->form.prog.update(this.name);