private void btn_PreviewQuestion_Click(object sender, EventArgs e)
{
PreviewQuestion Preview = new PreviewQuestion();
Preview.QuestionPreview = txt_ContentQuestion.Text;
foreach (Answer_MultiSelect multichoice in flp_addAnswer.Controls)
{
Preview.AnswerPreview.Add(multichoice.txt_AnswerContent.Text);
}
Preview.ShowDialog();
}