设置

dateTimePicker1.ShowUpDown = true;

怎么样? 这显示了一个旋转按钮控件(上-下控件)，而不是一个下拉日历?

是否已将DateTimePicker.Format设置为Custom?

This show a spin button control (up-down control), rather than a drop-down calendar ?

Have you set DateTimePicker.Format to Custom ?

timePicker.Format=DateTimePickerFormat.Custom