问题
I want to increase the size of popup as well as the size of font of popup of datetime picker. The change is done in above red block portion of datetime picker.
回答1:
You cannot change the size, it is hard-baked in the native Windows component that implements the calendar. Also obvious from the MonthCalendar class (same animal as the DTP dropdown), note how dragging the sizing handles does nothing at all. And how changing the Font has no effect.
Inflexible but not really a problem, any other program that runs on the user's machine displays the exact same calendar in the exact same size. If the user has a visual impairment that gives her trouble using the calendar then she'll change the system font size or video DPI setting.
来源：https://stackoverflow.com/questions/9428764/how-can-i-change-the-size-of-popup-of-datetime-picker-in-net