It seems that your real question is, "How do I convert a string value into a numeric value?"
Inside your loop, the only line you need is
schools[i] = Convert.ToInt32(SchoolListArr[i]);
You can use a cast instead, if you want; personally, I try to use .Net methods rather than language-specific syntax.
Move the declaration of
schools
to before the loop -- there is no need to keep recreating it -- make it an array of
int
and initialize it to have
SchoolListArr.Length
elements. I believe the
writeline
should be after the loop.