Hi Ismailc,
From my experience, there is no properties to directly modify the border color and drop down button color of the ComboBox and the DateTimePicker. We need to create our custom control, and draw the border, the drop down button by ourselves.
These are some samples shows how to create custom ComboBox:
http://beta.codeproject.com/KB/combobox/zsepcmb.aspx?display=Print
http://beta.codeproject.com/KB/combobox/CustomComboBox.aspx
http://www.codeproject.com/KB/combobox/CustComboBox.aspx
To create custom DateTimePicker, we can follow the same way. Do not forget to use the MonthCalendar control as the drop down form.
Regards,
Aland Li
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