Question

It seems as though String.Format won’t format a string as an input. Am I doing something wrong, or is this just native behavior?

Input : 0.37

This doesn’t work.

string x = String.Format('{0:P}', myString) 

Output : 0.37

This does.

string x = String.Format('{0:P}', Convert.ToDecimal(myString)) 

Output : 37.00 %

Answer 1

I believe this is expected behavior for ‘composite formatting’.

Your first example is attempting to apply numerical formatting rules to a string. Your second example is attempting to apply numerical formatting rules to a number that can have decimal positions.

See this article on MSDN for more information.