How to round double numbers in C#.NET

decimal b = 1.55555555

Math.Round(b, 4); //returns 1.5556

see this example

double a = "2222.2349";//This is Input

string b = Math.Round(a, 3).ToString("0000.0000");
//-> 2222.2350

string c = Math.Round(a, 2).ToString("0000.0000");
//-> 2222.2300

string d = Math.Round(a, 1).ToString("0000.0000");
//-> 2222.2000

string f = Math.Round(a, 0).ToString("0000.0000");
//-> 2222.0000

Happy Coding!
:)

txt2.Text = Math.Round(Convert.ToDouble(txt1.Text),4, MidpointRounding.AwayFromZero).ToString();

I doubt you ever need to round anything. Sometimes it is required, but very rarely. Usually, you only need to give a string representation of the rounded number. Even though it looks like it is done through rounding, this is not exactly so.

The thing is: .NET FCL gives you ready-to-use methods for doing it the way you never round anything by yourself. This is much better, because you don't risk loosing accuracy of calculation by some accidental mistake.

To do such conversion, you need to use the method double.ToString(string format). Read about format string and rounding here:
http://msdn.microsoft.com/en-us/library/kfsatb94.aspx[^],
http://msdn.microsoft.com/en-us/library/dwhawy9k.aspx[^],
http://msdn.microsoft.com/en-us/library/0c899ak8.aspx[^].

—SA

Use Math.round method for the above conversion