This 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.
At a Glance
| Header file: | Winuser.h |
| Windows CE versions: | 1.0 and later |
Syntax
int MessageBox(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption,
UINT uType);
Parameters
hWnd
[in] Handle to the owner window of the message box to be created. If this parameter is NULL, the message box has no owner window.
lpText
[in] Long pointer to a null-terminated string that contains the message to be displayed.
lpCaption
[in] Long pointer to a null-terminated string used for the dialog box title. If this parameter is NULL, the default title “Error” is used.
uType
[in] 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:
| Value | Description |
| 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:
| Value | Description |
| MB_ICONEXCLAMATION, MB_ICONWARNING | 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, MB_ICONERROR, MB_ICONHAND | A stop-sign icon appears in the message box. |
Specify one of the following flags to indicate the default button:
| Value | Description |
| 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. |
The following flag is the default modality of the dialog box:
| Value | Description |
| 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 popup windows are not. |
In addition, you can specify the following flags:
| Value | Description |
| 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. |
Return Values
Zero indicates that there is not enough memory to create the message box.
Upon success, one of the values described in the following table is returned.
| Value | Description |
| 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 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.
Remarks
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 control in a dialog box.
See Also