Мне нравится этот. он ограничивается только проверкой сумм в долларах, но может быть настроен на более общую работу.
public static string ToWrittenValueString(this decimal number)
{
// convert the number to a usable value
var numStr = Math.Round(number,2,MidpointRounding.AwayFromZero).ToString();
// seperate the value before and after the decimal point
var numParts = numStr.Split('.');
IList<string> txt = new List<string>();
// get the total number of digits in the number before the decimal point.
var digits = numParts[0].Length;
for (int n = 1; n <= digits; n++)
{
//this handles the hundreds, hundred thousands and hundred millions place
if (n % 3 == 0)
{
txt.Add("HUNDRED");
txt.Add(onesAndTeens[int.Parse(numParts[0][digits - n].ToString())]);
}
// this handles the two digits preceding the hundreds, hundred thousands and hundred millions place
if (n % 3 == 2 | (n == digits & n % 3!=0))
{
// this get's the integer equivilent of only those two digits
var tmpnum = int.Parse(string.Join("", numParts[0].Skip(digits-n).Take(n % 3 == 2? 2: 1)));
// this get's the name of the three didget grouping that the current digit's of interest are in i.e. thousand, million etc...
txt.Add(digitGroupName[((n - n % 3) / 3)]);
// if the integer equivilent is less than 20 we use the onesAndTeens lookup table
// if the integer equivilent is twenty or more we use the tens lookup for the most significant digit and the onesAndTeens lookup for the least significant digit
if (tmpnum < 20)
txt.Add(onesAndTeens[tmpnum]);
else
txt.Add(string.Format("{0}{1}", tens[(tmpnum - tmpnum % 10) / 10], onesAndTeens[tmpnum % 10] ));
}
}
return string.Format("{0} AND {1}/100 DOLLARS", string.Join(" ", txt.Reverse()), numParts[1]);;
}
private static string[] onesAndTeens = new string[20] { "", "ONE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT","NINE","TEN","ELEVEN","TWELVE", "THIRTEEN","FOURTEEN","FIFTEEN","SIXTEEN","SEVENTEEN","EIGHTEEN","NINETEEN"};
private static string[] tens = new string[10] {"","","TWENTY","THIRTY","FOURTY","FIFTY","SIXTY","SEVENTY","EIGHTY","NINETY"};
private static string[] digitGroupName = new string[4] {"","THOUSAND","MILLION","BILLION" };