After my background worker is complete, I want to change labels on my form. Where should I add this code?

Question

After the background worker is done doing its process, I want to change the text on certain labels on the form.

Here's the Button that fires the backgroundworker:

private void btnProcessImages_Click(object sender, EventArgs e)
        {
            DialogResult processImagesWarnMsg = MessageBox.Show("You're about to process images, are you sure?", "Warning!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button2);

            if (processImagesWarnMsg == DialogResult.Yes)
            {
                DisableAllButtons();

                if (!processImagesWorker.IsBusy)
                {
                    processImagesWorker.RunWorkerAsync();
                }
                //The problem here is that the below will run BEFORE the worker is complete. Where should I place the below method in my code? 
                //ResetDirectoryStatistics();
            }
        }

Here's the method that changes text for the labels on the form:

private void ResetDirectoryStatistics()
        {
            lblSelectedDirectory.Text = "N/A";
            lblTotalNumberOfFilesInDirectory.Text = "N/A";
            lblTotalNumberOfSupportedFilesInDirectory.Text = "N/A";
            lblTotalNumberOfUnsupportedFilesInDirectory.Text = "N/A";
            lblTotalNumberOfPoliciesInDirectory.Text = "N/A";
        }

When dealing with the background worker, where should I place the ResetDirectoryStatistics method? I cannot place it in the "DoWork" method of the backgroundworker because that would be cross-threading. And if I place the method right after processImagesWorker.RunWorkerAsync();, it'll execute itself before RunWorker is complete.

Answer 1

You should call your method in the RunWorkerCompleted event of the background worker. This event uses the UI thread, so no cross-threading issue to fear.

Answer 2

You just need to put all of your code in the RunWorkerCompleted event of the BackgroundWorker .

It will even take care of ensuring that the event runs in the UI thread, so you don't need to worry about invoking or anything like that.