Using InvariantCultureIgnoreCase instead of ToUpper for case-insensitive string comparisons

Question

On this page, a commenter writes:

Do NOT ever use .ToUpper to insure comparing strings is case-insensitive.

Instead of this:

Answer 1

In short, it's optimized by the CLR (less memory as well).

Further, uppercase comparison is more optimized than ToLower(), if that tiny degree of performance matters.

In response to your example there is a faster way yet:

String.Equals(type.Name, controllerName + "Controller", 
              StringComparison.InvariantCultureIgnoreCase);