日本語 Comparer

Comparer_jp

日本語を比較(ソート)するための Comparer クラスと
static なメソッド Compare() です
string.Compare() の代わりに Comparer_jp.Compare() を使用します

Comparer_jp.cs

using System.Globalization;

namespace System.Text
{
    public sealed class Comparer_jp : IComparer<string>
    {
        public readonly CompareOptions options;

        public readonly CompareInfo compare_info;

        public Comparer_jp(bool ignorecase = false)
        {
            options = CompareOptions.IgnoreWidth | CompareOptions.IgnoreKanaType;

            if (ignorecase)
            {
                options |= CompareOptions.IgnoreCase;
            }

            var ci = new CultureInfo("ja-JP");

            compare_info = ci.CompareInfo;
        }

        public int Compare(string? s1, string? s2)
        {
            return compare_info.Compare(s1, s2, options);
        }

        public readonly static Comparer_jp comparer = new Comparer_jp();
        public readonly static Comparer_jp comparer_ignorecase = new Comparer_jp(true);

        public static int Compare(string? s1, string? s2, bool ignorecase = false)
        {
            if (ignorecase)
            {
                return comparer_ignorecase.Compare(s1, s2);
            }
            else
            {
                return comparer.Compare(s1, s2);
            }
        }
    }
}