I think I might have an idea what you mean, however, I'm a little confused because of some of your terminology.
Think of this as - the process my mind went through to translate your sentence. And yes, I could be an idiot.
"not part of a database" - I think you mean it's not data that exists as records in a table. This is what is called an unbound control or unbound text box.
The term field is used almost exclusively as a field in a table or query. Field is actually an Access term - a more generic word would be Columns that's used in most of the rest of the database world.
Another point is, most of the time that somebody wants to sort text boxes, they want to sort the data in them, and it's because they're using a form bound to a query or table that happens to display the data in text boxes. This, of course, can't be true because you said it's not part of a database.
However, you could sort the text within a text box but then you'd have to choose on what criteria. Generally, you're going to have to write a code module that grabs the text and then parses the word into an array and then puts them in order. There are a variety of simple sorting techniques that should work.
If it's actually a combobox or list box, you're going to have to do the same thing, however, walking through the text will require a slightly different technique to reference each item in the list.
If you're actually in (laymans term) the viewpoint that looks a lot like a spreadsheet - you are no longer actually working with a textbox. Sorting it is as simple as clicking on the header fields and making it sort.
There are other questions I might ask, however, that's a lot of speculation. More details would let us get more specific.