如何使用RegEx匹配C＃中的字符串列表？

I need to find all the regex matches from a list of strings. For example, I need to be able to take the string "This foo is a foobar" and match any instances of either "foo" or "bar". What would the correct pattern be for this? Also, what input sanitation would I need to do to prevent the inputted text from breaking the pattern?I need to find all the regex matches from a lis