BUT ....
Subtstring will throw an exception if any of its arguments resolve to
indexes not within the string it is being applied to:
EXAMPLE
string s = "AB";
string left5 = s.Substring( s.Length-5, 5 ); <<<< throws exception
here
Try substring.
string s = "Hello world";
string left5 = s.Substring( s.Length-5, 5 );
Console.WriteLine("S = {0}", left5 );
Output:
S = world
Matt