C# Language Using a BackgroundWorker to complete a task.


The following example demonstrates the use of a BackgroundWorker to update a WinForms ProgressBar. The backgroundWorker will update the value of the progress bar without blocking the UI thread, thus showing a reactive UI while work is done in the background.

namespace BgWorkerExample
    public partial class Form1 : Form

    //a new instance of a backgroundWorker is created.
    BackgroundWorker bgWorker = new BackgroundWorker();
    public Form1()

        prgProgressBar.Step = 1;

        //this assigns event handlers for the backgroundWorker
        bgWorker.DoWork += bgWorker_DoWork;
        bgWorker.RunWorkerCompleted += bgWorker_WorkComplete;

        //tell the backgroundWorker to raise the "DoWork" event, thus starting it.
        //Check to make sure the background worker is not already running.

    private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
        //this is the method that the backgroundworker will perform on in the background thread.
        /* One thing to note! A try catch is not necessary as any exceptions will terminate the backgroundWorker and report 
          the error to the "RunWorkerCompleted" event */

    private void bgWorker_WorkComplete(object sender, RunWorkerCompletedEventArgs e)
        //e.Error will contain any exceptions caught by the backgroundWorker
        if (e.Error != null)
            MessageBox.Show("Task Complete!");
            prgProgressBar.Value = 0;

    // example method to perform a "long" running task.
    private void CountToY()
        int x = 0;

        int maxProgress = 100;
        prgProgressBar.Maximum = maxProgress;

        while (x < maxProgress)
            Invoke(new Action(() => { prgProgressBar.PerformStep(); }));
            x += 1;


The result is the following...

enter image description here enter image description here