private void TxtCurrentPage_KeyDown(object sender, KeyEventArgs e) { if (e.KeyCode == System.Windows.Forms.Keys.Enter || e.KeyCode == System.Windows.Forms.Keys.Tab) { int pageNumber; if (int.TryParse(txtCurrentPage.Text, out pageNumber)) { DocumentViewer1.GoToPage(pageNumber); } else { txtCurrentPage.Text = DocumentViewer1.CurrentPage.ToString(); } } }