She is well known for her role as Colleen McMurphy on the ABC television show China Beach ( 1988 â `` 1991 ) , Katherine Mayfair on Desperate Housewives ( 2007 â `` 2010 ) and Megan Hunt on Body of Proof ( 2011 â `` present ) . She is known for her role as Colleen McMurphy on the ABC television show China Beach ( 1988 â `` 1991 ) , Katherine Mayfair on Desperate Housewives ( 2007 â `` 2010 ) , Megan Hunt on Body of Proof ( 2011 â `` present ) and , as a voice-actress , Lois Lane in the DC Animated Universe as well as the television series The Batman .