You can use an Anonymous Function:
WebBrowser browser = new WebBrowser();
browser.Dock = DockStyle.Fill;
browser.Url = new System.Uri("http://google.com");
tabControl1.TabPages.Add(new TabPage("Aba " + (tabControl1.TabCount + 1).ToString()));
tabControl1.TabPages[tabControl1.TabCount - 1].Controls.Add(browser);
browser.ProgressChanged += new WebBrowserProgressChangedEventHandler( delegate (object sender, WebBrowserProgressChangedEventArgs events)
{
if ((int)events.CurrentProgress > 0)
{
toolStripProgressBar1.Maximum = (int)events.MaximumProgress;
toolStripProgressBar1.Value = (int)events.CurrentProgress;
}
});