What is the correct way to compare char ignoring case?

Question

I\'m wondering what the correct way to compare two characters ignoring case that will work for all cultures. Also, is Comparer.Default the best way

Answer 1

I would recommend comparing uppercase, and if they don't match then comparing lowercase, just in case the locale's uppercasing and lowercasing logic behave slightly different.

Addendum

For example,

int CompareChar(char c1, char c2)
{
    int  dif;

    dif = char.ToUpper(c1) - char.ToUpper(c2);
    if (diff != 0)
        dif = char.ToLower(c1) - char.ToLower(c2);
    return dif;
}