wtf, white dress shirts with white sneakers? What are you, falko?  You ought to be banned for that silly comment.
 
If you look like an arsehole, you’re not getting in. Period.

Well, I have never come across any places with strict dress codes that require a collared shirt and dress pants.  Nice jeans and nice shirt work perfectly fine, nice tshirt even works perfectly fine, and this is more or less what most of the Europeans will be wearing, but trendy, not frat-boy sloppy.  Some places have an issue with gym shoes, but this depends on the fads of the year in question.  Ask around when you get there.  I’ve never had an issue in Europe with dress codes.

Even if you get in, you have to think about what other people will think. (Babes for example.)