Can I display float as percent value with positive/negative sign just with formatting string?

Question

For example, input 0.12 should produce string "+12%" and -0.42 should produce "-42%". I'd like to achieve it without writing any actual code, only by defining format string.

Answer 1

You can use conditional string formating:

public static void Main()
{
    string format = "+#.00 %;-#.00 %;+0.00 %";
    Console.WriteLine((-0.12).ToString(format));
    Console.WriteLine((0.12).ToString(format));
    Console.WriteLine(0.ToString(format));
}

which outputs:

-12.00 %
+12.00 %
+0.00 %

Unfortunately there is no value for PercentPositivePattern that allows to specify a plus sign application wide.