Defines a collation method.

Collation means sorting pieces of text. It needs to take into account characters, accents and case; spaces and punctuation are usually ignored. It differs from ordinary methods of sorting in that it is locale-dependent - different languages use different ordering methods. Additionally, multiple collation methods may exist within the same locale.

A collation method provides the collation keys and other data needed to customise collation; the Mem and TDesC16 collation functions (e.g. Mem::CompareC()) perform the collation. Note that these functions use the standard collation method for the current locale - you only need to specify an object of class TCollationMethod to customise this collation scheme. Collation methods can be retrieved using member functions of the Mem class. Each one has a unique identifier.

A collation method specifies a main table of collation keys, and optionally an overriding table that contains keys for which the values in the main table are overridden. A collation key table (TCollationKeyTable) is the set of collation keys: primary (basic character identity), secondary (accents and diacritics) and tertiary (case). The quaternary key is the Unicode character values themselves.

The simplest way to customise a collation method is to create a local copy of the standard collation method and change it. For example, you could use the standard method, but not ignore punctuation and spaces:

TCollationMethod m = *Mem::CollationMethodByIndex(0); // get the standard method
m.iFlags |= TCollationMethod::EIgnoreNone; // dont ignore punctuation and spaces