That's a multi-part question that I won't answer in a single post. You can compare text using string.Compare, string.CompareOrdinal, or use some of the regular expression methods found in System.Text.RegularExpressions.RegEx class. That will tell you what's different. From there, you'd have to provide more information as to what you're trying to highlight, what control you're using to highlight, whether you're using Windows Forms or Web Forms, what problems you're having, etc.
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