How to Convert Persian Digits in variable to English Digits Using Culture?

Simply Use the code below :

private string changePersianNumbersToEnglish(string input)
{
  string[] persian = new string[10] { "۰", "۱", "۲", "۳", "۴", "۵", "۶", "۷", "۸", "۹" };

   for (int j=0; j<persian.Length; j++)
      input = input.Replace(persian[j], j.ToString());

   return input;
 }

I suggest two approaches to handle this issue(I Create an extension method for each of them):

1.foreach and replace

public static class MyExtensions
{
     public static string PersianToEnglish(this string persianStr)
     {
            Dictionary<char, char> LettersDictionary = new Dictionary<char, char>
            {
                ['۰'] = '0',['۱'] = '1',['۲'] = '2',['۳'] = '3',['۴'] = '4',['۵'] = '5',['۶'] = '6',['۷'] = '7',['۸'] = '8',['۹'] = '9'
            };
            foreach (var item in persianStr)
            {
                persianStr = persianStr.Replace(item, LettersDictionary[item]);
            }
            return persianStr;
     }
}

2.Dictionary.Aggregate

public static class MyExtensions
{
      public static string PersianToEnglish(this string persianStr)
      {
            Dictionary<string, string> LettersDictionary = new Dictionary<string, string>
            {
                ["۰"] = "0",["۱"] = "1",["۲"] = "2",["۳"] = "3",["۴"] = "4",["۵"] = "5",["۶"] = "6",["۷"] = "7",["۸"] = "8",["۹"] = "9"
            };
            return LettersDictionary.Aggregate(persianStr, (current, item) =>
                         current.Replace(item.Key, item.Value));
      }
}

More info about Dictionary.Aggregate: Microsoft

Usage:

string result = "۱۰۳۶۷۵۱".PersianToEnglish();