It 's no pleasure doing这个句型,为什么动词要用ing形式呢?为什么不用to do sth.

常见的带 no + n + doing/ to do sth
It's no good crying over spilt milk.覆水难收,世上无后悔药.后悔不管用.
It's no easy job persuading her to change her mind.
这种结构多为习惯表达,-ing 形式更常见,但 to do 在语法上也正确,但频率不高.