MessageBoxEx
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 wLanguageId parameter specifies
which set of language resources is used for the predefined push buttons. For
full descriptions of the other parameters of MessageBoxEx, see MessageBox1FW7BH .
int MessageBoxEx(
|
HWND hWnd, |
// handle of owner
window |
|
LPCTSTR lpText, |
// address of text
in message box |
|
LPCTSTR lpCaption, |
// address of title
of message box |
|
UINT uType, |
// style of message
box |
|
WORD wLanguageId |
// language
identifier |
|
); |
|
Parameters
hWnd
Identifies
the owner window of the message box to be created. If this parameter is NULL,
the message box has no owner window.
lpCaption
Points to a
null-terminated string containing the message to be displayed.
lpszTitle
Points to a
null-terminated string used for the dialog box title. If this parameter is
NULL, the default title Error is used.
uType
Specifies a
set of bit flags that determine the contents and behavior of the dialog box.
This parameter can be a combination of flags from the following groups of
flags.
Specify one
of the following flags to indicate the buttons contained in the message box:
|
Flag |
Meaning |
|
MB_ABORTRETRYIGNORE |
The message
box contains three push buttons: Abort, Retry, and Ignore. |
|
MB_OK |
The message
box contains one push button: OK. This is the default. |
|
MB_OKCANCEL |
The message
box contains two push buttons: OK and Cancel. |
|
MB_RETRYCANCEL |
The message
box contains two push buttons: Retry and Cancel. |
|
MB_YESNO |
The message
box contains two push buttons: Yes and No. |
|
MB_YESNOCANCEL |
The message
box contains three push buttons: Yes, No, and Cancel. |
Specify one
of the following flags to display an icon in the message box:
|
Flag |
Meaning |
|
MB_ICONEXCLAMATION,
|
An
exclamation-point icon appears in the message box. |
|
MB_ICONINFORMATION,
MB_ICONASTERISK |
An icon consisting
of a lowercase letter 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. |
Specify one
of the following flags to indicate the default button:
|
Flag |
Meaning |
|
MB_DEFBUTTON1 |
The first
button is the default button. MB_DEFBUTTON1
is the default unless MB_DEFBUTTON2, MB_DEFBUTTON3, or MB_DEFBUTTON4 is
specified. |
|
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. |
Specify one
of the following flags to indicate the modality of the dialog box:
|
Flag |
Meaning |
|
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 applications 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 application. All child windows of the parent of
the message box are automatically disabled, but popup 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
task 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 current application
without suspending other applications. |
In addition,
you can specify the following flags:
MB_DEFAULT_DESKTOP_ONLY
The desktop
currently receiving input must be a default desktop; otherwise, the function
fails. A default desktop is one an application runs on after the user has
logged on.
MB_HELP
Adds a Help
button to the message box. Choosing the Help button or pressing F1 generates a
Help event.
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, Windows 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
only: 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.
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 Windows
NT version 4.0, the value of MB_SERVICE_NOTIFICATION has changed. See WINUSER.H for the old and new values. Windows NT 4.0
provides backward compatibility for pre-existing services by mapping the old
value to the new value in the implementation of MessageBox and MessageBoxEx.
This mapping is only done for executables that have a version number, as set by
the linker, less than 4.0.
To build a
service that uses MB_SERVICE_NOTIFICATION, and can run on both Windows NT 3.x
and Windows NT 4.0, you have two choices.
|
1. At link-time, specify a version number less
than 4.0; or |
|
2. 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. |
MB_SERVICE_NOTIFICATION_NT3X
Windows NT
only: This value corresponds to the
value defined for MB_SERVICE_NOTIFICATION for Windows NT version 3.51.
wLanguageId
Specifies the
language in which to display the text contained in the predefined push buttons.
This value must be in the form returned by the MAKELANGID macro.
For a list of
the language identifiers supported by Win32, see Language Identifiers. Note that each localized
release of Windows typically contains resources only for a limited set of
languages. Thus, for example, the U.S. version offers LANG_ENGLISH, the French
version offers LANG_FRENCH, the German version offers LANG_GERMAN, and the Japanese
version offers LANG_JAPANESE. Each version offers LANG_NEUTRAL. This limits the
set of values that can be used with the wLanguageId parameter. Before
specifying a language identifier, you should enumerate the locales that are
installed on a system.
Return Values
If the
function succeeds, the return value is a nonzero menu-item value returned by
the dialog box.
|
Value |
Meaning |
|
IDABORT |
Abort
button was selected. |
|
IDCANCEL |
Cancel
button was selected. |
|
IDIGNORE |
Ignore
button was selected. |
|
IDNO |
No button
was selected. |
|
IDOK |
OK button
was selected. |
|
IDRETRY |
Retry
button was selected. |
|
IDYES |
Yes button
was selected. |
If a message
box has a Cancel button, the function returns the IDCANCEL value when either
the ESC
key or Cancel button is pressed. If the message box has no Cancel button,
pressing the ESC key has no effect.
If the
function fails, the return value is zero. To get extended error information,
call GetLastError.
Remarks
When you
create a system-modal message box to indicate that the system is low on memory,
the strings passed as the lpText and lpCaption parameters should
not be taken from a resource file, because an attempt to load the resource may
fail.
When an
application calls the MessageBoxEx function and specifies the
MB_ICONHAND and MB_SYSTEMMODAL flags for the uType parameter, the Win32
API displays the resulting message box regardless of available memory. When you
specify these flags, Windows limits the length of the message-box text to one
line.
If you create
a message box while a dialog box is present, use the handle of the dialog box
as the hWnd parameter. The hWnd parameter should not identify a
child window, such as a dialog box.
Windows
95: The system can support a maximum
of 16,364 window handles.
See Also