c# - FormatException when formatting TimeSpan number of days without leading zeroes -

according msdn, d format specifier outputs timespan.days property. when used in .tostring() method appears true:

timespan.fromdays(1).tostring("%d")

however, when used in string.format, specifier throws exception:

string.format("{0:d}", timespan.fromdays(1))  'string.format("{0:d}", timespan.fromdays(1))' threw exception of type 'system.formatexception'     base {system.systemexception}: {"input string not in correct format."} 

the dd specifier works fine, gives leading 0 (as intended).

why d specifier throw exception?

you missing %:

string.format("{0:%d}", timespan.fromdays(1)) 

according article linked (and example copied):

if "d" custom format specifier used alone, specify "%d" not misinterpreted standard format string.