C#

private void Form1_Load(object sender, EventArgs e)
    {
    WebBrowser wb = new WebBrowser();
    wb.Dock = DockStyle.Fill;
    Controls.Add(wb);
    wb.Url = new Uri("http://www.google.co.uk/search?hl=en&safe=off&q=How+do+I+use+a+progress+bar+in+c%23%3F&btnG=Search&meta=");
    WindowState = FormWindowState.Maximized;
    }

using System;
using System.Windows.Forms;

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        myProgressBar.ProgressChanged += myProgressBar_ProgressChanged;
        // myProgressBar.Value = 50;
    }

    void myProgressBar_ProgressChanged(object sender, EventArgs<int> e)
    {
        textBox.Text = string.Format("{0}%", e);
    }
}
public class MyProgressBar : ProgressBar
{
    public event EventHandler<EventArgs<int>> ProgressChanged;

    public new int Value
    {
        get { return base.Value; }
        set
        {
            if (value >= Minimum &&
                value <= Maximum &&
                value != base.Value)
            {
                base.Value = value;
                OnProgressChanged(new EventArgs<int>(value));
            }
        }
    }
    protected virtual void OnProgressChanged(EventArgs<int> e)
    {
        EventHandler<EventArgs<int>> eh = ProgressChanged;
        if (eh != null)
            eh(this, e);
    }
}

public class EventArgs<T> : EventArgs
{
    public EventArgs(T value)
    {
        Value = value;
    }
    public T Value
    {
        get;
        private set;
    }
    public override string ToString()
    {
        return Value.ToString();
    }
}