MCM_SETMONTHDELTA message

Sets the scroll rate for a month calendar control. The scroll rate is the number of months that the control moves its display when the user clicks a scroll button. You can send this message explicitly or by using the MonthCal_SetMonthDelta macro.

Parameters

wParam

Value representing the number of months to be set as the control's scroll rate. If this value is zero, the month delta is reset to the default, which is the number of months displayed in the control.

lParam

Must be zero.

Return value

Returns an INT value that represents the previous scroll rate. If the scroll rate was not previously set, the return value is zero.

Remarks

The PAGE UP and PAGE DOWN keys, VK_PRIOR and VK_NEXT, change the selected month by one, regardless of the number of months displayed or the value set by MCM_SETMONTHDELTA.

Requirements