C# - new CultureInfo instantiation performance

Question

I was wondering if it was a good practice to instantiate a CultureInfo object repeatdedly in a loop process (few thousand times). This object is required in many Date and String methods to force a specific culture when CurrentCulture may not be the right one.

var c = new CultureInfo("en-US", false);

What is the performance of a repeated instantiation?

Answer 1

One would think that the optimizer in the C# and/or the JIT compilers would have the smarts to recognize a loop-invariant expression and refactor outside of the loop. My inclination is to do such refactorings myself as is makes the code clearer.

Even better, use this method:

CultureInfo ci = CultureInfo.GetCultureInfo("en-US") ;

It gives you a cached, read-only instance, the instance will only be constructed once and thence retrieve from cache.

Better yet, for your stated purposes:

This [CultureInfo] object is required in many Date and String methods to force a specific culture when CurrentCulture may not be the right one.

use CultureInfo.InvariantCulture. That is what it exists for.

A third option, would be to create a static CultureInfo property holding a singleton reference to your fallback culture. Depending on your purposed, you might want to mark it as thread-local (static methods of CultureInfo are thread-safe; instance methods are not). Such a propery might look something like this:

public static string FallbackCultureId { get { return Configuration.AppSettings["FallbackConfigurationId"] ; } }

public static CultureInfo FallbackCultureInfo
{
  get { return fallBackCultureInfo ?? (fallBackCultureInfo=new CultureInfo(FallbackCultureId)) ; }            
}
[ThreadStatic] private static CultureInfo fallBackCultureInfo ;