query criteria format

I have a text box that is used to submit stock symbols that are to be saved in a sql table. The symbols are to be separated by a space or a comma (I don't know which, yet). I want to retrieve the symbols later to be used in a query, but I don't know how to get the symbols in the proper string format for the query, eg

The symbols are stored in the tables as: A B C D
The query string criteria would look like: IN('A', 'B', 'C', 'D')

The IN('A', 'B', 'C', 'D') citeria would be the values in the @.Symbol variable in this SPROC

SELECT a_Name_Symbol.Symbol, a_Financials.Revenue
FROM a_Financials INNER JOIN
a_Name_Symbol ON a_Financials.Symbol = a_Name_Symbol.Symbol
WHERE (a_Name_Symbol.Symbol @.Symbol)
ORDER BY a_Name_Symbol.Symbol

Is there a slick (ie easy) way to change the contents entered in the text box (A B C D) into IN('A', 'B', 'C', 'D') ?

Thanks,

PaulThis might not be the best way, but here goes:

string symbols = "'" + txtBox.Text.Replace(" ", "', '") + "'";