{
        webBrowser1.Navigating += new EventHandler<NavigatingEventArgs>(webBrowser1_Navigating);
    }

    void webBrowser1_Navigating(object sender, NavigatingEventArgs e)
    {
        string scheme = null;

        try
        {
            scheme = e.Uri.Scheme; // <- this is throwing an exception here
        }
        catch
        {
        }
        if (scheme == null || scheme == "file")
            return;
        // Not going to follow any other link
        e.Cancel = true;
        if (scheme == "shared")
        {

        }

void webBrowser1_Navigating(object sender, NavigatingEventArgs e)
    {
        String scheme = null;

        try
        {
            scheme = e.Uri.Scheme;
        }
        catch
        {
        }
        if (scheme == null || scheme == "file")
            return;
        // Not going to follow any other link
        e.Cancel = true;
        if (scheme == "http")
        {
            // Check if it's the "shared" URL
            if (e.Uri.Host == "shared")
            {
                // Start email
                EmailComposeTask emailComposeTask = new EmailComposeTask();
                emailComposeTask.Subject = "Sharing an app with you";
                emailComposeTask.Body = "You may like this app...";
                emailComposeTask.Show();
            }
            else
            {
                // start it in Internet Explorer
                WebBrowserTask webBrowserTask = new WebBrowserTask();
                webBrowserTask.Uri = new Uri(e.Uri.AbsoluteUri);
                webBrowserTask.Show();
            }
        }
        if (scheme == "mailto")
        {
            EmailComposeTask emailComposeTask = new EmailComposeTask();
            emailComposeTask.To = e.Uri.AbsoluteUri;
            emailComposeTask.Show();
        }
    }