String formatting: negative/positive floating point numbers

Question

How can I use String.Format in C# so doubles are displayed like this:

example:
___-1.000
____1.000
__100.123
-1000.321
_1000.214

etc...

Where _ is space (" ");

All I can do is String.Format("{0:F3}", -123.321);

Answer 1

You can use alignment:

String.Format("{0,10:F3}", -123.321)

where 10 is preffered length.

See Composite Formatting.