So, is it a list of strings or is it something more? If it is something more, which appears to be the case, why did you say otherwise? I'm sure that you're not trying to be misleading and vague and but you're not trying hard enough not to be either. Please remember that we only know what you tell us so please provide accurate and complete information.
Anyway, you can perform CRUD operations on any data stored in any manner. It's just a matter of how you implement the operations. If you're using an XML file then LINQ to XML comes to mind as a first option, although I've never used it.