is StringComparison.Ordinal the same as InvariantCulture for testing equality?

Question

From their brief summary descriptions, it sounds like the string comparison rules StringComparison.Ordinal and StringComparison.InvariantCulture are meant to differ in how they do sorting of strings. Is that all? i.e., does that mean we can use either string comparison rule when doing an equality comparison?

string.Equals(a, b, StringComparison....)

And for extra credit: does it make a difference to the answer if we compare OrdinalIgnoreCase and InvariantCultureIgnoreCase? How?

Please provide supporting argument and/or references.

Answer 1

It does matter, for example - there is a thing called character expansion

    var s1 = "Strasse";
    var s2 = "Straße";

    s1.Equals(s2, StringComparison.Ordinal);          // false
    s1.Equals(s2, StringComparison.InvariantCulture); // true

With InvariantCulture the ß character gets expanded to ss.