private void btnSoDoBan_Click(object sender, RoutedEventArgs e) { if (ucSoDoBan == null) { ucSoDoBan = new UserControlLibrary.UCSoDoBan(mTransit); ucSoDoBan.Width = spNoiDung.RenderSize.Width; ucSoDoBan.Height = spNoiDung.RenderSize.Height; } spNoiDung.Children.Clear(); spNoiDung.Children.Add(ucSoDoBan); }