A check box is a small square box with a label next to it. A user can turn a check box on or off by tapping it with the stylus or pressing the space bar when the check box has the keyboard focus. The box is empty in its default off state and has a check mark in it when it is turned on.
Check box
Applications display check boxes in a group box to permit the user to choose from a set of related but independent options. For example, an application might present a group of check boxes from which the user can select error conditions that produce warning beeps.
When the user selects a check box of any style, the check box receives the keyboard focus from Windows CE, which sends the check box's parent window a WM_COMMAND message containing the BN_CLICKED notification code. The parent window does not acknowledge this message if it comes from an automatic check box or automatic three-state check box because Windows CE automatically sets the check state for those styles. But the parent window must acknowledge the message if it comes from an application-defined check box or three-state check box because the parent window, not Windows CE, is responsible for setting the check state for those styles. Regardless of the check box style, Windows CE automatically repaints the check box once its state is changed.