如何在C＃中固定十进制值的点

Question

I have code in VB.net in below:

me.Index = Format(Convert.ToDouble(g.Trim()), "##.##")

result : 120.00

how do i same thing in C#. I don't use format function in C#. I just want result will not place more then two value after point. i mean if i send value 120.120000 then result will be 12.12

Answer 1

It's not clear what you mean by "I don't use format function in C#" but of course you could use string.Format . However, using double.ToString would probably be simpler:

Index = Convert.ToDouble(g.Trim()).ToString("0.##");

(I've changed the leading ## to 0 to ensure that there's always a leading digit, so you don't get ".5" for example. Obviously if you really want the leading digits to be optional, change it to "#.##" . I don't see a benefit in using ## as a prefix though.)

However:

• This will use the current culture's decimal separator; is that what you want, or do you always want to use . ?
• If the decimal representation of the number is important, you may well not want to use double at all. Are you sure you shouldn't be using decimal ?

Answer 2

你可以这样

decimal.Round(yourValue, 2, MidpointRounding.AwayFromZero);

Answer 3

Either you use this

var value = 2.346;
var str = value.ToString("0.00");

or

decimal.Round(yourValue, 2, MidpointRounding.AwayFromZero); //as in msdn site which rounds a decimal value to a specified precision.

or use Round function like this

decimal a = 1.994444M;

Math.Round(a, 2);