Try HTML Code Sniffer, a browser bookmarklet that runs javascript assertions on a page, that map to WCAG2A, AA, AAA or section 508.
HTML Code Sniffer also has a phantomjs command line runner that you could try integrating into a ASP.NET test suite.
The syntax looks like this: phantomjs HTMLCS_Run.js URL standard
" where standards are "WCAG2A", "WCAG2AA", "WCAG2AAA"
. It outputs a pipe delimited list of errors.