ProgressBar Example: Windows Forms

ProgressBar indicates visually the progress of an operation.

It is best used on a long-running computation or task. And the BackgroundWorker is often used to perform that task—it does not block the interface.

Example. Please add a ProgressBar control to your Windows Forms program by double-clicking on the ProgressBar entry in the Toolbox. For this example, we also need a BackgroundWorker—add one and then create the event handlers required.

BackgroundWorker

Note: We need the Load event handler, the DoWork event handler, and the ProgressChanged event handler.

Example that uses ProgressBar and BackgroundWorker: C#

using System.ComponentModel;
using System.Threading;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
	public Form1()
	{
	    InitializeComponent();
	}

	private void Form1_Load(object sender, System.EventArgs e)
	{
	    // Start the BackgroundWorker.
	    backgroundWorker1.RunWorkerAsync();
	}

	private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
	{
	    for (int i = 1; i <= 100; i++)
	    {
		// Wait 100 milliseconds.
		Thread.Sleep(100);
		// Report progress.
		backgroundWorker1.ReportProgress(i);
	    }
	}

	private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
	{
	    // Change the value of the ProgressBar to the BackgroundWorker progress.
	    progressBar1.Value = e.ProgressPercentage;
	    // Set the text.
	    this.Text = e.ProgressPercentage.ToString();
	}
    }
}

Starting the background task. In the Form1_Load event handler, please add a method call to the RunWorkerAsync method on the BackgroundWorker instance. This will create a thread and the DoWork method will begin.

Inside the DoWork event handler, we loop over the numbers 1 through 100. At each iteration, we wait one-tenth of a second. Then, we call the ReportProgress method on the BackgroundWorker instance.

And: In ProgressChanged, we set the value of the ProgressBar to the ProgressPercentage property of the ProgressChangedEventArgs argument.

Note: This will be the values 1 through 100. We also update the title text in the method.

Color. One of the useful properties on the ProgressBar is the ForeColor property. This can be set to a Color value to change the color of the bar itself that is drawn on the screen. It is often better to use the default color.

Note: In this screenshot, we see a yellow bar instead of the default blue bar. This is likely a bad design decision.

Summary. The ProgressBar control is often used in conjunction with a threading mechanism such as BackgroundWorker. With its many options, the ProgressBar makes a suitable widget for letting your users know the application is still active.

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