在搜索List c＃之前规范化输入字符串

I am creating a multi form application which has a series of validation test before the user can save the form. One of those validation functions needs evaluate if the user has entered certain keywords, such as 'Unkown', 'TBA', 'N/A'.I need to begin by normalizing the input string, to strip all unwanted characters such as Whitespace, and extra casing such as 'UNkown', 'tBA'. This then needs to be checked against my I am creating a multi form application which ha