.net - Replace value dynamically with regular expression -

i have url like

http://www.somesite.com/$(somekey).php 

i have dictionary includes these keys, need using regex replace $(*) value in dictionary labeled key.

how can that?

a thing perhaps:

url = regex.replace(url , @"\$\(([^)]+)\)", delegate(match m){ return dict[m.groups[1]]; });