c# - What is the percentage format string to always display the sign?

Question

I want to display 0.12345 as "+12.3%". Format string "P1" or "p1" gives "12.3%". I have tried both "+P1" and "+p1" to no avail.

string sFoo = 0.12345.ToString("P1");

Update

I should have emphasized that I always want the proper sign, not "+". If the number is -0.12345, "P1" works exactly as I want: "-12.3%".

Answer 1

Not quite using P1, but same result:

0.12345.ToString("+#.#%;-#.#%");

If you prefer at least one leading digit (e.g. "+0.23%" instead of "+.23%"):

0.12345.ToString("+0.#%;-0.#%"));

Same for trailing digits (e.g. "+14.0%" instead of "+14%"):

0.12345.ToString("+0.0%;-0.0%"));

Reference: https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-numeric-format-strings#the--section-separator