All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Wearing the indecent dress described in the question which maintains neither modesty nor covering is one of the common evils that weddings involve. A woman is required to wear a covering dress in weddings and in other occasions as well. Sorrowfully, the Muslims have copied all these traditions from the West. There is an intense desire to imitate Westerners, even at the expense of our religion and the traditions according to which we have been raised through complying by the Quran and the Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam. All those who have religious zeal and piety are required to avoid these evil deeds. We ask Allaah to help Muslims to keep adherent to their religious teachings.
Allaah Knows best.