Comparing two strings, ignoring case in C# [duplicate]

Which of the following two is more efficient? (Or maybe is there a third option that's better still?)

string val = "AStringValue";

if (val.Equals("astringvalue", StringComparison.InvariantCultureIgnoreCase))

OR

if (val.ToLowerCase() == "astringvalue")

?

Solution 1:

If you're looking for efficiency, use this:

string.Equals(val, "astringvalue", StringComparison.OrdinalIgnoreCase)

Ordinal comparisons can be significantly faster than culture-aware comparisons.

ToLowerCase can be the better option if you're doing a lot of comparisons against the same string, however.

As with any performance optimization: measure it, then decide!

Solution 2:

The first one is the correct one, and IMHO the more efficient one, since the second 'solution' instantiates a new string instance.