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The MessageBoxEx function creates, displays, and operates a message box. The message box contains an application-defined message and title, plus any combination of predefined icons and push buttons. The buttons are in the language of the system user interface.
Currently MessageBoxEx and MessageBox work the same way.
int MessageBoxEx(
HWND hWnd,
LPCTSTR lpText,
LPCTSTR lpCaption,
UINT uType,
WORD wLanguageId
);
MB_DEFBUTTON2 The second button is the default button. MB_DEFBUTTON3 The third button is the default button. MB_DEFBUTTON4 The fourth button is the default button. To indicate the modality of the dialog box, specify one of the following values. MB_APPLMODAL The user must respond to the message box before continuing work in the window identified by the hWnd parameter. However, the user can move to the windows of other threads and work in those windows. Depending on the hierarchy of windows in the application, the user may be able to move to other windows within the thread. All child windows of the parent of the message box are automatically disabled, but pop-up windows are not.
MB_APPLMODAL is the default if neither MB_SYSTEMMODAL nor MB_TASKMODAL is specified.
MB_SYSTEMMODAL Same as MB_APPLMODAL except that the message box has the WS_EX_TOPMOST style. Use system-modal message boxes to notify the user of serious, potentially damaging errors that require immediate attention (for example, running out of memory). This flag has no effect on the user's ability to interact with windows other than those associated with hWnd. MB_TASKMODAL Same as MB_APPLMODAL except that all the top-level windows belonging to the current thread are disabled if the hWnd parameter is NULL. Use this flag when the calling application or library does not have a window handle available but still needs to prevent input to other windows in the calling thread without suspending other threads. To specify other options, use one or more of the following values. MB_DEFAULT_DESKTOP_ONLY Windows NT/2000/XP: Same as MB_SERVICE_NOTIFICATION except that the system will display the message box only on the default desktop of the interactive window station. For more information, see Window Stations. Windows NT 4.0 and earlier: If the current input desktop is not the default desktop, MessageBoxEx fails.
Windows 2000/XP: If the current input desktop is not the default desktop, MessageBoxEx does not return until the user switches to the default desktop.
Windows 95/98/Me: This flag has no effect.
MB_RIGHT The text is right-justified. MB_RTLREADING Displays message and caption text using right-to-left reading order on Hebrew and Arabic systems. MB_SETFOREGROUND The message box becomes the foreground window. Internally, the system calls the SetForegroundWindow function for the message box. MB_TOPMOST The message box is created with the WS_EX_TOPMOST window style. MB_SERVICE_NOTIFICATION Windows NT/2000/XP: The caller is a service notifying the user of an event. The function displays a message box on the current active desktop, even if there is no user logged on to the computer. Terminal Services: If the calling thread has an impersonation token, the function directs the message box to the session specified in the impersonation token.
If this flag is set, the hWnd parameter must be NULL. This is so the message box can appear on a desktop other than the desktop corresponding to the hWnd.
For more information on the changes between Microsoft Windows NT 3.51 and Windows NT 4.0, see Remarks.
For information on security considerations in regard to using this flag, see Interactive Services.
MB_SERVICE_NOTIFICATION_NT3X Windows NT/2000/XP: This value corresponds to the value defined for MB_SERVICE_NOTIFICATION for Windows NT version 3.51. For more information on the changes between Windows NT 3.51 and Windows NT 4.0, see Remarks.
If a message box has a Cancel button, the function returns the IDCANCEL value if either the ESC key is pressed or the Cancel button is selected. If the message box has no Cancel button, pressing ESC has no effect.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
If the function succeeds, the return value is one of the following menu-item values.
When you use a system-modal message box to indicate that the system is low on memory, the strings pointed to by the lpText and lpCaption parameters should not be taken from a resource file because an attempt to load the resource may fail.
If you create a message box while a dialog box is present, use a handle to the dialog box as the hWnd parameter. The hWnd parameter should not identify a child window, such as a control in a dialog box.
Windows 95/98/Me: The system can support a maximum of 16,364 window handles.
Windows NT/2000/XP: The value of MB_SERVICE_NOTIFICATION changed starting with Windows NT 4.0. Windows NT 4.0 provides backward compatibility for pre-existing services by mapping the old value to the new value in the implementation of MessageBoxEx. This mapping is done only for executables that have a version number less than 4.0, as set by the linker.
To build a service that uses MB_SERVICE_NOTIFICATION, and can run on both Microsoft Windows NT 3.x and Windows NT 4.0, you can do one of the following.
At link-time, specify a version number less than 4.0 At link-time, specify version 4.0. At run-time, use the GetVersionEx function to check the system version. Then when running on Windows NT 3.x, use MB_SERVICE_NOTIFICATION_NT3X; and on Windows NT 4.0, use MB_SERVICE_NOTIFICATION. Windows 95/98/Me: Even though MessageBoxExW exists, it is supported by the Microsoft Layer for Unicode on Windows 95/98/Me Systems to give more consistent behavior across all Windows operating systems.
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Notebook exported on Monday, 7 July 2008, 18:56:50 PM Eastern Daylight Time