dynamic set css in c#

.selected { font-style: bold; }

When a link is clicked set that link's CSS class to "selected" and the others to "";

EDIT: To accommodate for existing Css Class

const string MY_CLASS = "links";
lb1.CssClass = MY_CLASS + " selected"; // selected
lb.CssClass = MY_CLASS; // not selected

Image Rotation in W8 Store app

http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh700359.aspx