private void NextButton_Click(object sender, RoutedEventArgs e)
 {
     if (CodeBehind.index > CodeBehind._frames.Count - 1)
     {
         return;
     }
     CodeBehind.index++;
     CodeBehind.Seteaza_Controler(this);
 }
 private void PreviousButton_Click(object sender, RoutedEventArgs e)
 {
     if (CodeBehind.index - 1 <= 0)
     {
         return;
     }
     CodeBehind.index--;
     CodeBehind.Seteaza_Controler(this);
 }