Question

What I’m trying to do, when we click on button in radform1(Parent), hide radform1 then update the text/label/radgrid header text values in Form1(child form),
once we close the Form1(child form)..close radform1(Parent) as well.

I’m getting a error message : Invalid OPeration Exception was Un-HandledCross-thread operation not valid
Control ‘radPageView1 has been accessed from a thread other than the one on which it was created.

How can i use the invoke or action method to fix this problem?? I couldn’t understand the concept exactly.. Please explain to me what should i do here…Any help is appreciated!

Form1 frm = new Form1();
        private void radButton1_Click(object sender, EventArgs e) // French Version Button
        {
            timer1.Enabled = true;
            radProgressBar1.Visible = true;
            frm.radGridView1.Columns[0].HeaderText = "Test"; // Change the Radgrid Header Text at Col[0]

        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            ticks++;
            radProgressBar1.Value1 = ticks;
            if (ticks != 100) return;
            timer1.Enabled = false;
            ticks = 0;

            frm.FormClosed += (_, args) => frm.Close();
            frm.Hide();
            frm.Show();

        }

Answer 1

I don’t know if I understand well, but I think you need something like this:

public static void InvokeIfRequired(this Form c, Action<Form> action)
        {
            if (c.InvokeRequired)
            {
                try { c.Invoke(new Action(() => action(c))); }
                catch { }
            }
            else
            {
                action(c);
            }
        }

and call

frm.InvokeIfRequired((_)=>{frm.ChangeSomethingInTheUI();});

in this way you are sure that the action will be performed inside the right thread.

Hope this helps.