Update progress bar in another form while task is running

Question

**Ultimately I am going to have four tasks running concurrently and have another form that contains four progress bars. I would like for each progress bar to update as it\'s wo

Answer 1

The TPL adds the IProgress interface for updating the UI with the progress of a long running non-UI operation.

All you need to do is create a Progress instance in your UI with instructions on how to update it with progress, and then pass it to your worker which can report progress through it.

public partial class MyMainForm : System.Windows.Forms.Form
{
    private async void btn_doWork_Click(object sender, EventArgs e)
    {
        MyProgressBarForm progressForm = new MyProgressBarForm();
        progressForm.Show();
        Progress progress = new Progress();
        progress.ProgressChanged += (_, text) =>
            progressForm.updateProgressBar(text);
        await Task.Run(() => RunComparisons(progress));
        progressForm.Close();
    }
    private void RunComparisons(IProgress progress)
    {
        foreach (var s in nodeCollection)
        {
            Process(s);
            progress.Report("hello world");
        }
    }
}
public partial class MyProgressBarForm : System.Windows.Forms.Form
{
    public void updateProgressBar(string updatedTextToDisplay)
    {
        MyProgressBarControl.Value++;
        myLabel.Text = updatedTextToDisplay;
    }
}

This lets the Progress Form handle displaying progress to the UI, the working code to only handle doing the work, the main form to simply create the progress form, start the work, and close the form when done, and it leaves all of the work of keeping track of progress and marhsaling through the UI thread to Progress. It also avoids having multiple UI thread; your current approach of creating and manipulating UI components from non-UI threads creates a number of problems that complicates the code and makes it harder to maintain.