private async void buttonOk_Click(object sender, EventArgs e) { buttonOk.Enabled = false; string URL = FixUrl(textBoxUrl.Text); try { // Use the Uri class for quick validation of the URL. new Uri(URL); } catch { MessageBox.Show("The URL is invalid", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Error); return; } bookmark.Title = textBoxCaption.Text; bookmark.Url = URL; bookmark.FavIcon = await Bookmark.GetFavIconAsyc(URL); Close(); }