ProgressBar not Updating Fix - C#

by test , at 6:56 PM , have 0 Comments

It has been sited by many StackOverflow questions that, usually when using a BackgroundWorker, your ProgressBar will not update correctly when using C#. I do not know why this happens, however some people suggest that it is because of the threaded interface in Windows Vista and Windows 7.The ProgressBar would get to about 75% full when it should have been at its maximum, and would revert back to 0% before it was fully drawn. Here is what that looked like:

And this is the example code I used:

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            for (int i = 1; (i <= 100); i++)
            {
                    // Perform a time consuming operation and report progress.
                    System.Threading.Thread.Sleep(20);
                    backgroundWorker1.ReportProgress((i ));
            }
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
            if (progressBar1.Maximum == e.ProgressPercentage)
                progressBar1.Value = 0;
        }

However, Mark Lansdown from StackOverflow found a very useful solution, taken from this question.

What he suggested is to draw the value, then draw the value minus 1, because that would force a redraw on the ProgressBar. To to that, I just changed my ProgressChanged event to:

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
            if (e.ProgressPercentage != 0)
                progressBar1.Value = e.ProgressPercentage - 1;
            progressBar1.Value = e.ProgressPercentage;
            if (progressBar1.Maximum == e.ProgressPercentage)
                progressBar1.Value = 0;
        }

And the result is that the ProgressBar will now be smoothly redrawn to 100% before it is reverted.