private async void ThemThuChibutton_Click(object sender, RoutedEventArgs e)
 {
     ctdlThemThuChi ttc = new ctdlThemThuChi();
     await ttc.ShowAsync();
 }
 private async void ThemThuChibutton_Click(object sender, RoutedEventArgs e)
 {
     ctdlThemThuChi ttc = new ctdlThemThuChi();
     await ttc.ShowAsync();
 }