Why does string.Compare seem to handle accented characters inconsistently?

Question

If I execute the following statement:

string.Compare(\"mun\", \"mün\", true, CultureInfo.InvariantCulture)

The result is \'-1\', indicating

Answer 1

It looks like the accented character is only being used in a sort of "tie-break" situation - in other words, if the strings are otherwise equal.

Here's some sample code to demonstrate:

using System;
using System.Globalization;

class Test
{
    static void Main()
    {
        Compare("mun", "mün");
        Compare("muna", "münb");
        Compare("munb", "müna");
    }

    static void Compare(string x, string y)
    {
        int result = string.Compare(x, y, true, 
                                   CultureInfo.InvariantCulture));

        Console.WriteLine("{0}; {1}; {2}", x, y, result);
    }
}

(I've tried adding a space after the "n" as well, to see if it was done on word boundaries - it isn't.)

Results:

mun; mün; -1
muna; münb; -1
munb; müna; 1

I suspect this is correct by various complicated Unicode rules - but I don't know enough about them.

As for whether you need to take this into account... I wouldn't expect so. What are you doing that is thrown by this?