Some persian extension methods

PersianDateExtensionMethods.cs

// source code orginaly from http://www.dotnettips.info/post/1244/

/*
Use as extension method:
var date1 = DateTime.Now.ToPesianDateString("yyyy/MM/dd");
var date2 = DateTime.Now.ToPeianDateString("dddd, dd MMMM,yyyy");
 
//Output:
//1391/12/13
//یکشنبه, 13 اسفند,1391


Use as default culture:
Thread.CurrentThread.CurrentCulture = Thread.CurrentThread.CurrentUICulture = PersianDateExtensionMethods.GetPersianCulture();
 
var d1 = DateTime.Now.ToString();
//Output : 1391/12/13 11:25:44 ب.ظ

*/

using System;
using System.Globalization;
using System.Reflection;
 
namespace System 
{
    public static class PersianDateExtensionMethods
    {
        private static CultureInfo _Culture;
        public static CultureInfo GetPersianCulture()
        {
            if (_Culture == null)
            {
                _Culture = new CultureInfo("fa-IR");
                DateTimeFormatInfo formatInfo = _Culture.DateTimeFormat;
                formatInfo.AbbreviatedDayNames = new[] { "ی", "د", "س", "چ", "پ", "ج", "ش" };
                formatInfo.DayNames = new[] { "یکشنبه", "دوشنبه", "سه شنبه", "چهار شنبه", "پنجشنبه", "جمعه", "شنبه" };
                var monthNames = new[]
                {
                    "فروردین", "اردیبهشت", "خرداد", "تیر", "مرداد", "شهریور", "مهر", "آبان", "آذر", "دی", "بهمن",
                    "اسفند",
                    ""
                };
                formatInfo.AbbreviatedMonthNames =
                    formatInfo.MonthNames =
                    formatInfo.MonthGenitiveNames = formatInfo.AbbreviatedMonthGenitiveNames = monthNames;
                formatInfo.AMDesignator = "ق.ظ";
                formatInfo.PMDesignator = "ب.ظ";
                formatInfo.ShortDatePattern = "yyyy/MM/dd";
                formatInfo.LongDatePattern = "dddd, dd MMMM,yyyy";
                formatInfo.FirstDayOfWeek = DayOfWeek.Saturday;
                System.Globalization.Calendar cal = new PersianCalendar();
 
                FieldInfo fieldInfo = _Culture.GetType().GetField("calendar", BindingFlags.NonPublic | BindingFlags.Instance);
                if (fieldInfo != null)
                    fieldInfo.SetValue(_Culture, cal);
 
                FieldInfo info = formatInfo.GetType().GetField("calendar", BindingFlags.NonPublic | BindingFlags.Instance);
                if (info != null)
                    info.SetValue(formatInfo, cal);
 
                _Culture.NumberFormat.NumberDecimalSeparator = "/";
                _Culture.NumberFormat.DigitSubstitution = DigitShapes.NativeNational;
                _Culture.NumberFormat.NumberNegativePattern = 0;
            }
            return _Culture;
        }
 
        public static string ToPesianDateString(this DateTime date,string format = "yyyy/MM/dd")
        {
            return date.ToString(format,GetPersianCulture());
        }
    }
}

PersianExtensions.cs

public static class PersianExtensions
{
    public static string FixPersianChars(this string Value)
    {
        return Value.Replace('ی', 'ي').Replace("ک", "ك");
    }
    
    public static string ToPersianNumber(this string input)
    {
        if (String.IsNullOrEmpty(input)) 
            return "";
        //۰ ۱ ۲ ۳ ۴ ۵ ۶ ۷ ۸ ۹
        input = input.Replace("0", "۰");
        input = input.Replace("1", "۱");
        input = input.Replace("2", "۲");
        input = input.Replace("3", "۳");
        input = input.Replace("4", "۴");
        input = input.Replace("5", "۵");
        input = input.Replace("6", "۶");
        input = input.Replace("7", "۷");
        input = input.Replace("8", "۸");
        input = input.Replace("9", "۹");
        return String.Format(Format, input);
    }
}