[C#] Formatage des nombres et culture

using System;
using System.Collections.Generic;
using System.Globalization;

namespace Helpers
{
    public class Format
    {
        public static NumericFormat Numeric { get { return NumericFormat.Instance; } }
        public static DateFormat Date { get { return DateFormat.Instance; } }

        public static void Initialize(
            String emptyString,
            CultureInfo defaultCulture,
            CultureInfoCollection collection)
        {
            if (defaultCulture == null)
                throw new ArgumentNullException("defaultCulture");
            if (collection == null)
                throw new ArgumentNullException("collection");

            collection.Add("Default", defaultCulture);

            Numeric.Initialize(emptyString, collection);
            Date.Initialize(emptyString, collection);
        }
    }
    public abstract class TypeFormat
    {
        public String EmptyString { get; set; }
        public CultureInfo DefaultCulture { get; set; }

        internal abstract void Initialize(
            String emptyString,
            CultureInfoCollection collection);
    }
    public class NumericFormat
        : TypeFormat
    {
        #region Singleton
        private static readonly NumericFormat instance = new NumericFormat();
        internal static NumericFormat Instance { get { return instance; } }
        static NumericFormat() { }
        private NumericFormat() { }
        #endregion

        #region Initialization
        internal override void Initialize(
            String emptyString,
            CultureInfoCollection collection)
        {
            EmptyString = emptyString;
            Collection = collection;
        }
        #endregion

        #region Properties
        private CultureInfoCollection Collection { get; set; }
        #endregion

        #region Public Methods
        public String NumberFormatDecimals(Double numeric, String culture = null)
        {
            return numeric.ToString("N", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormatDecimals(Double? numeric)
        {
            if (numeric.HasValue)
                return NumberFormatDecimals(numeric);
            else return EmptyString;
        }
        public String NumberFormat(Double numeric, String culture = null)
        {
            return numeric.ToString("N0", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormat(Double? numeric)
        {
            if (numeric.HasValue)
                return NumberFormat(numeric);
            else return EmptyString;
        }

        public String NumberFormatDecimals(Single numeric, String culture = null)
        {
            return numeric.ToString("N", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormatDecimals(Single? numeric)
        {
            if (numeric.HasValue)
                return NumberFormatDecimals(numeric);
            else return EmptyString;
        }
        public String NumberFormat(Single numeric, String culture = null)
        {
            return numeric.ToString("N0", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormat(Single? numeric)
        {
            if (numeric.HasValue)
                return NumberFormat(numeric);
            else return EmptyString;
        }

        public String NumberFormat(Int16 numeric, String culture = null)
        {
            return numeric.ToString("N0", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormat(Int16? numeric)
        {
            if (numeric.HasValue)
                return NumberFormat(numeric);
            else return EmptyString;
        }
        public String NumberFormat(Int32 numeric, String culture = null)
        {
            return numeric.ToString("N0", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormat(Int32? numeric)
        {
            if (numeric.HasValue)
                return NumberFormat(numeric);
            else return EmptyString;
        }
        public String NumberFormat(Int64 numeric, String culture = null)
        {
            return numeric.ToString("N0", Collection.GetCulture(culture).NumberFormat);
        }
        public String NumberFormat(Int64? numeric)
        {
            if (numeric.HasValue)
                return NumberFormat(numeric);
            else return EmptyString;
        }

        public String PercentFormatDecimals(Double percent, String culture = null)
        {
            return percent.ToString("P", Collection.GetCulture(culture).NumberFormat);
        }
        public String PercentFormatDecimals(Double? percent)
        {
            if (percent.HasValue)
                return PercentFormatDecimals(percent);
            else return EmptyString;
        }
        public String PercentFormat(Double percent, String culture = null)
        {
            return percent.ToString("P0", Collection.GetCulture(culture).NumberFormat);
        }
        public String PercentFormat(Double? percent)
        {
            if (percent.HasValue)
                return PercentFormat(percent);
            else return EmptyString;
        }

        public String CurrencyFormat(Double currency, String culture = null)
        {
            return currency.ToString("C0", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormat(Double? currency)
        {
            if (currency.HasValue)
                return CurrencyFormat(currency.Value);
            else return EmptyString;
        }
        public String CurrencyFormatDecimals(Double currency, String culture = null)
        {
            return currency.ToString("C", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormatDecimals(Double? currency)
        {
            if (currency.HasValue)
                return CurrencyFormatDecimals(currency.Value);
            else return EmptyString;
        }
        public String CurrencyFormat(Int32 currency, String culture = null)
        {
            return currency.ToString("C0", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormat(Int32? currency)
        {
            if (currency.HasValue)
                return CurrencyFormat(currency.Value);
            else return EmptyString;
        }
        public String CurrencyFormat(Int64 currency, String culture = null)
        {
            return currency.ToString("C0", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormat(Int64? currency)
        {
            if (currency.HasValue)
                return CurrencyFormat(currency.Value);
            else return EmptyString;
        }
        public String CurrencyFormat(Single currency, String culture = null)
        {
            return currency.ToString("C0", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormat(Single? currency)
        {
            if (currency.HasValue)
                return CurrencyFormat(currency.Value);
            else return EmptyString;
        }
        public String CurrencyFormatDecimals(Single currency, String culture = null)
        {
            return currency.ToString("C", Collection.GetCulture(culture).NumberFormat);
        }
        public String CurrencyFormatDecimals(Single? currency)
        {
            if (currency.HasValue)
                return CurrencyFormatDecimals(currency.Value);
            else return EmptyString;
        }
        #endregion
    }
    public class DateFormat
        : TypeFormat
    {
        #region Singleton
        private static readonly DateFormat instance = new DateFormat();
        internal static DateFormat Instance { get { return instance; } }
        static DateFormat() { }
        private DateFormat() { }
        #endregion

        #region Initialization
        internal override void Initialize(
            String emptyString,
            CultureInfoCollection collection)
        {
            EmptyString = emptyString;
            Collection = collection;
        }
        #endregion

        #region Properties
        private CultureInfoCollection Collection { get; set; }
        #endregion

        #region Public Methods
        public String ShortDate(DateTime date, String culture = null)
        {
            return date.ToString("d", Collection.GetCulture(culture).DateTimeFormat);
        }
        public String ShortDate(DateTime? date)
        {
            if (date.HasValue)
                return LongDate(date.Value);
            else return EmptyString;
        }
        public String LongDate(DateTime date, String culture = null)
        {
            return date.ToString("D", Collection.GetCulture(culture).DateTimeFormat);
        }
        public String LongDate(DateTime? date)
        {
            if (date.HasValue)
                return LongDate(date.Value);
            else return EmptyString;
        }

        public String ShortTime(DateTime date, String culture = null)
        {
            return date.ToString("t", Collection.GetCulture(culture).DateTimeFormat);
        }
        public String ShortTime(DateTime? date)
        {
            if (date.HasValue)
                return ShortTime(date.Value);
            else return EmptyString;
        }
        public String LongTime(DateTime date, String culture = null)
        {
            return date.ToString("T", Collection.GetCulture(culture).DateTimeFormat);
        }
        public String LongTime(DateTime? date)
        {
            if (date.HasValue)
                return LongTime(date.Value);
            else return EmptyString;
        }

        public String FullDateTime(DateTime date, String culture = null)
        {
            return date.ToString("F", Collection.GetCulture(culture).DateTimeFormat);
        }
        public String FullDateTime(DateTime? date)
        {
            if (date.HasValue)
                return FullDateTime(date.Value);
            else return EmptyString;
        }
        #endregion
    }
    public class CultureInfoCollection
        : Dictionary<String, CultureInfo>
    {
        public CultureInfo GetCulture(String name)
        {
            try
            {
                if(String.IsNullOrEmpty(name))
                    return this["Default"];

                if (name.Equals("Current", StringComparison.InvariantCultureIgnoreCase))
                    return System.Threading.Thread.CurrentThread.CurrentCulture;

                if (ContainsKey(name))
                    return this[name];
                else
                {
                    CultureInfo wanted = new CultureInfo(name);
                    Add(wanted.Name, wanted);
                    return wanted;
                }
            }
            catch
            {
                return this["Default"];
            }
        }
    }
}