GlobalizationExtensions.cs

namespace System.Globalization
{
    public static class GlobalizationExtensions
    {
        private const CompareOptions ValidCompareMaskOffFlags = ~(CompareOptions.IgnoreCase | CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreSymbols | CompareOptions.IgnoreKanaType | CompareOptions.IgnoreWidth | CompareOptions.StringSort);

        public static StringComparer GetStringComparer(this CompareInfo compareInfo, CompareOptions options)
        {
            if (compareInfo == null)
            {
                throw new ArgumentNullException("compareInfo");
            }
            switch (options)
            {
            case CompareOptions.Ordinal:
                return StringComparer.Ordinal;
            case CompareOptions.OrdinalIgnoreCase:
                return StringComparer.OrdinalIgnoreCase;
            default:
                if ((options & ~(CompareOptions.IgnoreCase | CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreSymbols | CompareOptions.IgnoreKanaType | CompareOptions.IgnoreWidth | CompareOptions.StringSort)) != 0)
                {
                    throw new ArgumentException(Environment.GetResourceString("Argument_InvalidFlag"), "options");
                }
                return new CultureAwareComparer(compareInfo, options);
            }
        }
    }
}