What do mean by "parsing an array"?

You could just put your list of substrings to match in an array, then use  
Array.Exists() or Array.IndexOf() to see if the substring is in the  
array.  There are similar methods you could use with the List<> class.  
Alternatively, you could probably use the RegEx class to see if there's a  
match.  I think you can use a search string like "[aa|bb|cc|...]" on your  
string; if your string is only two characters long and there's a match,  
then you know your substring was one of the items in the RegEx.

Personally, I'd use the array look-up method, but I suppose if you're  
really against using an array or List<>, RegEx would do.

Basically, there's any number of ways to do what you want.  Without a more  
precise problem description, it's hard to offer anything other than very  
general advice.

Pete

Not sure if I quite understand what you are trying to do but something like
this should work.

           string[] twoCharString = { "AA", "BB", "CC", "DD" };
           MessageBox.Show((twoCharString.Contains("BB") ? "Yes" :
"Nope"));

You can use the Contains method of a string.

-Pramod Anchuparayil