BM_SETSTYLE

This message alters the style of buttons. If the style contained in the wParam parameter differs from the existing style, the button is redrawn in the new style.

Parameter Description  

wParam Specifies the style value. For a complete description of possible button styles, see Table R.1, “Button Styles.”  
lParam Specifies whether or not the buttons are to be redrawn. If lParam is zero, the buttons will not be redrawn. If lParam is nonzero, they will be redrawn.  

Comments

Table R.1 describes the available button styles:

Table R.1 Button Styles

Value Meaning

BS_AUTOCHECKBOX Identical to BS_CHECKBOX, except that the button automatically toggles its state whenever the user clicks it.
BS_AUTORADIOBUTTON Identical to BS_RADIOBUTTON, except that the button is checked, the application is notified by BN_CLICKED, and the checkmarks are removed from all other radio buttons in the group.
BS_AUTO3STATE Identical to BS_3STATE, except that the button automatically toggles its state when the user clicks it.
BS_CHECKBOX Designates a box that may be checked; its border is bold when the user clicks the button. Any text appears to the right of the box.
BS_DEFPUSHBUTTON Designates a button with a bold border. This button represents the default user response. Any text is displayed within the button. Windows sends a message to the parent window when the user clicks the button.
BS_GROUPBOX Designates a rectangle into which other buttons are grouped. Any text is displayed in the rectangle's upper-left corner.
BS_LEFTTEXT Causes text to appear on the left side of the radio button or check-box button. Use this style with the BS_CHECKBOX, BS_RADIOBUTTON, or BS_3STATE styles.
BS_OWNERDRAW Designates an owner-draw button. The parent window is notified when the button is clicked. Notification includes a request to paint, invert, and disable the button.
BS_PUSHBUTTON Designates a button that contains the given text. The control sends a message to its parent window whenever the user clicks the button.
BS_RADIOBUTTON Designates a small circular button that can be checked; its border is bold when the user clicks the button. Any text appears to the right of the button. Typically, two or more radio buttons are grouped together to represent mutually exclusive choices, so no more than one button in the group is checked at any time.
BS_3STATE Identical to BS_CHECKBOX, except that the box can be grayed as well as checked. The grayed state typically is used to show that a check box has been disabled.