How to compare two strings and their upper and lower case signs

Question

Let\'s say I have 2 strings.First string is x = \"abc\" and the second one is y = \"ABC\".When I write in c# following code:

if(x == y)

or

Answer 1

First, you should decide whether you compare strings in culture dependent or independent way (e.g. in Russian Culture letters "E" and "Ё" often treats as being the same; Finnish tends to treat "V" and "W" as being the same etc.). Next you should choose whether use or not use case ("a" v. "A"). So there're 6 possible comparisons:

Ordinal (culture independent) comparisons:

// Ignore case comparison
Boolean equals = String.Equals(x, y, StringComparison.OrdinalIgnoreCase);
// Case comparison
Boolean equals = String.Equals(x, y, StringComparison.Ordinal);

Current culture comparisons:

// Current culture, ignore case comparison
Boolean equals = String.Equals(x, y, StringComparison.CurrentCulture);
// Current culture, case comparison
Boolean equals = String.Equals(x, y, StringComparison.CurrentCultureIgnoreCase);

Explicit culture comparisons:

CultureInfo culture = new CultureInfo("Ru-ru"); // <- Or whatever you want

// Explicit culture, ignore case comparison
Boolean equals = culture.CompareInfo.Compare(x, y, CompareOptions.IgnoreCase);
// Explicit culture, case comparison
Boolean equals = culture.CompareInfo.Compare(x, y, CompareOptions.None);