Cheque-writing applications require the conversion of a currency amount to be converted into text so that the words can be printed on the cheque. Other applications also require this. In this example WPF program we’ll convert a number to dollars and cents.
Below is the XAML code from the file MainWindow.xaml. Under that is the code-behind. This post contains all of the sourse code you need to build this project.
<Window x:Class="ConvertCurrencyToWords.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:ConvertCurrencyToWords"
mc:Ignorable="d"
WindowStartupLocation="CenterScreen"
Title="ConvertCurrencyToWords" Height="270" Width="420">
<StackPanel Margin="6,6,6,6" Background="#A4C2F8C3">
<TextBlock TextWrapping="Wrap">Enter in a number to have it converted to English words. Be sure to
just enter the digits and any decimal places. No punctuation such as dollar signs are allowed.
This program can convert positive numbers only.</TextBlock>
<TextBox Name="txtboxNumber" Width="140" Margin="4,4,4,4" MaxLength="15"></TextBox>
<Button Name="btnConvert" Height="26" Width="80" Click="BtnConvert_Click" Margin="4,4,4,4">Convert</Button>
<TextBox Name="txtblkWords" TextWrapping="Wrap" Margin="4,4,4,4" PreviewTextInput="TxtblkWords_PreviewTextInput"></TextBox>
</StackPanel>
</Window>
Below is the C# code behind.
using System;
using System.Windows;
namespace ConvertCurrencyToWords
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void BtnConvert_Click(object sender, RoutedEventArgs e)
{
string strNumberIn = txtboxNumber.Text;
int numberOfDecimals = 0;
try
{
bool b = double.TryParse(strNumberIn, out double NumberIn);
if (b)
{
if (strNumberIn.Contains(",") || strNumberIn.Contains("-"))
{
throw new System.ArgumentException("All characters must be digits. No negative numbers and no commas. Use periods to separate dollars and cents.", strNumberIn.ToString());
}
int decimalPlace = strNumberIn.IndexOf(".");
if (decimalPlace == -1) // there is NO decimal place here
{
numberOfDecimals = 0;
}
else
{ // Yes we have a decimal place
numberOfDecimals = strNumberIn.Length - decimalPlace - 1;
}
if (numberOfDecimals < 3)
{
// Must remove any leading zeros.
strNumberIn = strNumberIn.TrimStart(new Char[] { '0' });
txtblkWords.Text = ConvertToWords(strNumberIn);
}
else
{
throw new System.ArgumentException("Maximum of two decimal places.", strNumberIn.ToString());
}
}
else
{
throw new System.ArgumentException("All characters must be digits. No commas, no negative numbers, no spaces and no other punctuation such as currency symbols.", strNumberIn.ToString());
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Convert Currency to Words");
}
}
private static string ConvertToWords(string strNumberIn)
{
string strConverted = "", strWholeNumber = "", strFractionalNumber = "", strDollars = "Dollars", pointStr = "";
string strCents = "";
try
{
int decimalPlace = strNumberIn.IndexOf(".");
if (decimalPlace >= 0)
{
strWholeNumber = strNumberIn.Substring(0, decimalPlace);
strFractionalNumber = strNumberIn.Substring(decimalPlace + 1);
strDollars = strDollars + " and";
strCents = "Cents" + strCents;
pointStr = ConvertDecimals(strFractionalNumber);
}
else
{
// no decimal place given therefore just do whole number no cents.
strWholeNumber = strNumberIn;
}
strConverted = string.Format("{0} {1}{2} {3}",
ConvertWholeNumber(strWholeNumber).Trim(), strDollars, pointStr, strCents);
}
catch { }
return strConverted;
}
private static string ConvertDecimals(string strFractionalNumber)
{
// strFractionalNumber is everything after the decimal point (cents)
string engOne = "", cd = "";
if (strFractionalNumber.Length == 0)
{
engOne = "Zero";
}
if (strFractionalNumber.Length == 1)
{
if (strFractionalNumber == "0")
{ // they put "?.0"
engOne = "Zero";
}
else
{ // they put "?.1" or "?.2" or "?.3" or and so on
strFractionalNumber = strFractionalNumber + "0";
engOne = ConvertWholeNumber(strFractionalNumber);
}
}
if (strFractionalNumber.Length == 2)
{
if (strFractionalNumber == "00")
{
engOne = "Zero";
}
else
{
engOne = ConvertWholeNumber(strFractionalNumber);
}
}
cd += " " + engOne;
return cd;
}
private static string ConvertWholeNumber(string Number)
{
string word = "";
try
{
bool isDone = false; //test if already translated
//if (Number == "") Number = "0"; code smell here.
bool b = Double.TryParse(Number, out double ddd);
if (!b) return "Zero"; // we got empty string so zero dollars
double dblAmt = Convert.ToDouble(Number);
if (Number != "")
{
if (dblAmt > 0)
{
int numDigits = dblAmt.ToString().Length;
Number = dblAmt.ToString();
int pos = 0; //store digit grouping
string place = ""; //digit grouping name:hundres,thousand,etc...
switch (numDigits)
{
case 1://ones' range
word = ones(Number); isDone = true; break;
case 2://tens' range
word = tens(Number); isDone = true; break;
case 3://hundreds' range
pos = (numDigits % 3) + 1; place = " Hundred "; break;
case 4://thousands' range
case 5:
case 6: pos = (numDigits % 4) + 1; place = " Thousand "; break;
case 7://millions' range
case 8:
case 9: pos = (numDigits % 7) + 1; place = " Million "; break;
case 10://Billions's range
case 11:
case 12: pos = (numDigits % 10) + 1; place = " Billion "; break;
case 13: // Trillions range
case 14:
case 15: pos = (numDigits % 13) + 1; place = " Trillion "; break;
case 16: // Quadrillion range
case 17:
case 18: pos = (numDigits % 16) + 1; place = " Quadrillion "; break;
case 19: // Quintillion range
case 20:
case 21: pos = (numDigits % 19) + 1; place = " Quintillion "; break;
default: isDone = true; break;
}
if (!isDone)
{ // if transalation is not done, continue...(Recursion comes in now!!)
if (Number.Substring(0, pos) != "0" && Number.Substring(pos) != "0")
{
try
{
word = ConvertWholeNumber(Number.Substring(0, pos)) +
place + ConvertWholeNumber(Number.Substring(pos));
}
catch { }
}
else
{
word = ConvertWholeNumber(Number.Substring(0, pos)) +
ConvertWholeNumber(Number.Substring(pos));
}
}
//ignore digit grouping names
if (word.Trim().Equals(place.Trim())) word = "";
}
}
}
//
catch { } // Error in form here. Code smell.
return word.Trim();
}
private static string ones(string Number)
{
int _Number = Convert.ToInt32(Number);
string name = "";
switch (_Number)
{
//case 0: name = "Zero"; break; // ??????? added
case 1: name = "One"; break;
case 2: name = "Two"; break;
case 3: name = "Three"; break;
case 4: name = "Four"; break;
case 5: name = "Five"; break;
case 6: name = "Six"; break;
case 7: name = "Seven"; break;
case 8: name = "Eight"; break;
case 9: name = "Nine"; break;
}
return name;
}
private static string tens(string Number)
{
int intNumber = Convert.ToInt32(Number);
string name = null;
switch (intNumber)
{
//case 0: name = "Zero"; break; this doesn't work
case 10: name = "Ten"; break;
case 11: name = "Eleven"; break;
case 12: name = "Twelve"; break;
case 13: name = "Thirteen"; break;
case 14: name = "Fourteen"; break;
case 15: name = "Fifteen"; break;
case 16: name = "Sixteen"; break;
case 17: name = "Seventeen"; break;
case 18: name = "Eighteen"; break;
case 19: name = "Nineteen"; break;
case 20: name = "Twenty"; break;
case 30: name = "Thirty"; break;
case 40: name = "Fourty"; break;
case 50: name = "Fifty"; break;
case 60: name = "Sixty"; break;
case 70: name = "Seventy"; break;
case 80: name = "Eighty"; break;
case 90: name = "Ninety"; break;
default:
if (intNumber > 0)
{
name = tens(Number.Substring(0, 1) + "0") + " "
+ ones(Number.Substring(1));
}
break;
}
return name;
}
private void TxtblkWords_PreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)
{
}
}
}