c＃ToString一个十进制和强制+符号和数字小数位

Question

How can I do two things in tostring format:

1. Display number to x decimal places
2. Also force a + sign so that negative an positive numbers lineup in nice columns.

string fmt = "+N" + dp + ";-N" + dp;
Console.WrtieLine(Open.ToString(fmt))

Does not work?

Answer 1

You'll need to create a custom format string to do what you want. http://msdn.microsoft.com/en-us/library/0c899ak8.aspx tells you about these but the below is a quick example of one thing that does the trick.

double num = 1111.019123;
int dp = 2;
string format = String.Format("+#.{0};-#.{0}",new string ('#',dp));
Console.WriteLine(num.ToString(format));