Wedding Shoes Payless

I wear a wedding ….?
I'm not in marriage, but my boyfriend is the best man. Is it OK to wear a strapless little black dress (something like that … http://www.arrivez.ca/images/Sedona.jpg), black and white shoes … (.. like the black and white but not tie http://www.payless.com Huge .. / Catalog / productdetail.aspx? ItemCode = 56,232 & ProductColor = Blue & WIDTH = Regular and MCP = & Women's SLC and BLC WomensSandals = = WomensSandalsTrendy) and then my diamond necklace from my boyfriend, and outstanding black and white ..? I do not know if it was too?
The shoes are for casual, but I like the dress.
Bridal Insider: Unforgettable Advice From Lela Rose