An up-down control is a pair of arrow buttons that the user can click to increment or decrement a value, such as a scroll position or a number displayed in a companion control (called a buddy window).
Sets the radix base for an up-down control. The base value determines whether the buddy window displays numbers in decimal or hexadecimal digits. Hexadecimal numbers are always unsigned, and decimal numbers are signed.
Sets the Unicode character format flag for the control. This message allows you to change the character set used by the control at run time rather than having to re-create the control.
Sent by the operating system to the parent window of an up-down control when the position of the control is about to change. This happens when the user requests a change in the value by pressing the control's up or down arrow. The UDN_DELTAPOS message is sent in the form of a WM_NOTIFY message.