Right - your problem is that you're trying to parse it as a single
number. 1, 3, 5 represent three different options. You need to:

1) Split the string by commas
2) Parse each of them as an integer
3) Check if the test ID is equal to *any* of the integers

If the string is "1,3,5" and you want to read the string as individual  
integers separated by commas, then you may want to use the String.Split()  
method to get three different strings, each of which you can parse.

But it's not clear that's actually going to address your question.

In the VB code you posted, the code in the "Case" will be executed if the  
integer is _any_ of the three listed.  If your file actually specifies a  
string reading "1,3,5", does that mean you only want to execute the code  
if that string matches _all_ of the options?  Does it mean that you want  
to execute the code _once_ if the string matches _any_ of the options?  Or  
does it meant that for each integer in the string, you want to execute the  
code in that "Case"?  Or perhaps some other possibility I haven't even  
mentioned?

As you've asked it, your question is ambiguous and until you state your  
question more clearly, no one will be able to provide you with the details  
you want.

Pete