The following message-box styles are available.
MB_ABORTRETRYIGNORE The message box contains three pushbuttons: Abort, Retry, and Ignore.
MB_OK The message box contains one pushbutton: OK.
MB_OKCANCEL The message box contains two pushbuttons: OK and Cancel.
MB_RETRYCANCEL The message box contains two pushbuttons: Retry and Cancel.
MB_YESNO The message box contains two pushbuttons: Yes and No.
MB_YESNOCANCEL The message box contains three pushbuttons: Yes, No, and Cancel.
MB_APPLMODAL The user must respond to the message box before continuing work in the current window. However, the user can move to the windows of other applications and work in those windows. The default is MB_APPLMODAL if neither MB_SYSTEMMODAL nor MB_TASKMODAL is specified.
MB_SYSTEMMODAL All applications are suspended until the user responds to the message box. System-modal message boxes are used to notify the user of serious, potentially damaging errors that require immediate attention and should be used sparingly.
MB_TASKMODAL Similar to MB_APPLMODAL, but not useful within a Microsoft Foundation class application. This flag is reserved for a calling application or library that does not have a window handle available.
MB_ICONEXCLAMATION An exclamation-point icon appears in the message box.
MB_ICONINFORMATION An icon consisting of an "I" in a circle appears in the message box.
MB_ICONQUESTION A question-mark icon appears in the message box.
MB_ICONSTOP A stop-sign icon appears in the message box.
Message-Box Default Buttons
MB_DEFBUTTON1 The first button is the default. Note that the first button is always the default unless MB_DEFBUTTON2 or MB_DEFBUTTON3 is specified.
MB_DEFBUTTON2 The second button is the default.
MB_DEFBUTTON3 The third button is the default.