How to modify UI from an another thread?

Hi friends,

For testing and learning purposes, I tried to write a code which simulates some calculations. I used BackGroundWorker to avoid GUI freeze during calculation. My problem is that I want to make change in UI, for example, changing a button's text. I added it to DoWork section of my code. Consider that my operations order needs to be kept. There is runtime error says cross-thread exception. I think I have to use Invoke and Delegate for solving my problem. Please write me a code for solving this problem. I would learn from your code.

Thanks.

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
button1.Text = "processing";
int sum = 0;
for (int i = 0; i <= 100; i++)
{
Thread.Sleep(100);
sum = sum + i;
backgroundWorker1.ReportProgress(i);
if (backgroundWorker1.CancellationPending)
{
e.Cancel = true;
backgroundWorker1.ReportProgress(0);
return;
}
}
e.Result = sum;
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
label1.Text = e.ProgressPercentage + "%";
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
{
label1.Text = "Process canceled";
}
else if (e.Error != null)
{
label1.Text = e.Error.Message;
}
else
{
label1.Text = "Result: " + e.Result.ToString();
}
}
private void button1_Click(object sender, EventArgs e)
{
if (!backgroundWorker1.IsBusy)
{
backgroundWorker1.RunWorkerAsync();
}
else
{
MessageBox.Show("Busy processing!. Please wait...");
}
}
private void button2_Click(object sender, EventArgs e)
{
if (backgroundWorker1.IsBusy)
{
backgroundWorker1.CancelAsync();
}
else
{
label1.Text = "No operation is running to cancel.";
}
}
}