Error Message: Cross-thread operation not valid: Control ‘progressBar1’ accessed from a thread other than the thread it was created on.
This goes for any control that needs to be touched by a worker thread, you cannot do it directly. You must do a callback so the main UI thread actually does the update.
Reproduce the problem:
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;
System.Threading.Thread worker = new System.Threading.Thread(doWork);
worker.Start();
}
private void doWork()
{
for (int i = 0; i < progressBar1.Maximum; i++)
{
progressBar1.PerformStep();
}
}
Solution is:
Add this method, and instead of calling progressBar1.PerformStep(), call ActuallyPerformStep():
delegate void CallPerformStep(ProgressBar myProgressBar);
private void ActuallyPerformStep(ProgressBar myProgressBar)
{
if (myProgressBar.InvokeRequired)
{
CallPerformStep del = ActuallyPerformStep;
myProgressBar.Invoke(del, new object[] { myProgressBar });
return;
}
myProgressBar.PerformStep();
}
And now the main UI thread is calling the UI Control.
