Currency Formatting C# with Example

The "c" (or currency) format specifier converts a number to a string that represents a currency amount. 
string.Format("{0:c}", 112.236677) // $112.23 - defaults to system 
Precision 
Default is 2. Use c1, c2, c3 and so on to control precision. 
string.Format("{0:C1}", 112.236677) //$112.2 
string.Format("{0:C3}", 112.236677) //$112.237 
//$112.2367 
string.Format("{0:C4}", 112.236677) 
string.Format("{0:C9}", 112.236677) //$112.236677000 
Currency Symbol 
1. Pass CultureInfo instance to use custom culture symbol. 
string.Format(new CultureInfo("de-DE"), "{0:c}", 112.236677); //112,24 € 
string.Format(new CultureInfo("hi-IN"), "{0:c}", 112.236677); //D112.24 
string.Format(new CultureInfo("en-US"), "{0:c}", 112.236677); //$112.24 
2. Use any string as currency symbol. Use NumberFormatInfo as to customize currency symbol. 
NumberFormatInfo nfi = new CultureInfo( "en-US", false ).NumberFormat; 
nfi = (NumberFormatInfo) nfi.Clone(); 
nfi.CurrencySymbol = "?"; 
 

string.Format(nfi, "{0:C}", 112.236677); //?112.24 
nfi.CurrencySymbol = "?%^&"; 
string.Format(nfi, "{0:C}", 112.236677); //?%^&112.24 
Position of Currency Symbol 
Use CurrencyPositivePattern for positive values and CurrencyNegativePattern for negative values. 
NumberFormatInfo nfi = new CultureInfo( "en-US", false ).NumberFormat; 
nfi.CurrencyPositivePattern = 0; 
string.Format(nfi, "{0:C}", 112.236677); //$112.24 - default 
nfi.CurrencyPositivePattern = 1; 
string.Format(nfi, "{0:C}", 112.236677); //112.24$ 
nfi.CurrencyPositivePattern = 2; 
string.Format(nfi, "{0:C}", 112.236677); //$ 112.24 
nfi.CurrencyPositivePattern = 3; 
string.Format(nfi, "{0:C}", 112.236677); //112.24 $ 
Negative pattern usage is the same as positive pattern. A lot more use cases please refer to original link. 
Custom Decimal Separator 
NumberFormatInfo nfi = new CultureInfo( "en-US", false ).NumberFormat; 
nfi.CurrencyPositivePattern = 0; 
nfi.CurrencyDecimalSeparator = ".."; 
string.Format(nfi, "{0:C}", 112.236677); //$112..24