prevent rounding of decimals when using currency string format

问题

I have some decimal data coming from an external service. I need to format the data to 2 decimal places as it is represents money, but if I use the standard C format, I rounds the number:

var x = 42.999m;

var y = string.Format("{0:C}", x);

This results in y containing £43.00. How can I have it round down to £42.99?

(Note that this question is not the same)

回答1:

If you want to use a non-default rounding strategy, you'd need to do something like:

var x = 42.999m;

var y = string.Format("{0:C}", Math.Floor(x * 100) / 100);

Math.Floor rounds down; however it doesn't take a number of decimal places, so you have to force the 2 decimal place behaviour.

回答2:

although this question has been solved but i suggest you to use

var y = String.Format("{0:c3}",x);
// "{0:C3}" is for -123.456 ("C3", en-US) -> ($123.456)

From here

来源：https://stackoverflow.com/questions/6042262/prevent-rounding-of-decimals-when-using-currency-string-format