C# String comparisons: Difference between CurrentCultureIgnoreCase and InvariantCultureIgnoreCase

Question

When doing a string comparison in C#, what is the difference between doing a

string test = "testvalue"; test.Equals("TESTVALUE", StringComparison.CurrentCultureIgnoreCase); 

and

string test = "testvalue"; test.Equals("TESTVALUE", StringComparison.InvariantCultureIgnoreCase); 

... and is it important to include that extra parameter, anyway?

Answer 1

The other posts have given good advice, but I thought it might be nice to show an example of where it definitely makes a difference:

using System; using System.Globalization; using System.Threading;  class Test {     static void Main()     {         CultureInfo turkish = CultureInfo.CreateSpecificCulture("tr");         Thread.CurrentThread.CurrentCulture = turkish;                          // In Turkey, "i" does odd things         string lower = "i";         string upper = "I";                  // Prints False         Console.WriteLine(lower.Equals(upper,              StringComparison.CurrentCultureIgnoreCase));         // Prints True         Console.WriteLine(lower.Equals(upper,              StringComparison.InvariantCultureIgnoreCase));     } } 

(There are no doubt many other cases - this was just the first one I thought of.)