A message box is a special kind of modal dialog box that an application uses to display messages and prompt for simple input. A message box typically contains a text message and one or more predefined buttons. You do not need to provide a dialog box template or dialog box procedure for a message box. Windows creates the template based on the text and buttons you specify and supplies its own dialog box procedure.
Message box
Use the MessageBox function to create a message box, specifying the text and the number and types of buttons to display. Because Windows CE controls the creation and management of the message box, you do not provide a dialog box template and dialog box procedure. Windows CE creates its own template based on the text and buttons specified for the message box and supplies its own dialog box procedure.
Note As with dialog boxes, sometimes it is necessary for a message box to appear on top of all other windows. In particular, under low memory conditions, the System Out of Memory Dialog Box will send a WM_CLOSE message to an application. If the application is not in the foreground, any message box it puts up will be hidden behind the current foreground window unless you create the message box with the MB_SETFOREGROUND style. Because putting the message box in the foreground will not bring the application's main window forward, put any information in the message box that the user may need to decide what action to take.
The MessageBeep function, generally used with message boxes, plays a waveform sound. The waveform sound for each sound type is identified by an entry in the sounds section of the registry.
Message box styles supported by Windows CE are described in the following table.
| Message box style | Description |
|---|---|
| Buttons | |
| MB_ABORTRETRYIGNORE | The message box contains three buttons: Abort, Retry, and Ignore. |
| MB_OK | The message box contains one button: OK. |
| MB_OKCANCEL | The message box contains two buttons: OK and Cancel. |
| MB_RETRYCANCEL | The message box contains two buttons: Retry and Cancel. |
| MB_YESNO | The message box contains two buttons: Yes and No. |
| MB_YESNOCANCEL | The message box contains three buttons: Yes, No, and Cancel. |
| MB_DEFBUTTON1 | The first button is the default button. Note that the first button is always the default unless you specify MB_DEFBUTTON2. |
| MB_DEFBUTTON2 | The second button is the default button. |
| MB_DEFBUTTON3 | The third button is the default button. |
| Icons | |
| MB_ICONASTERISK MB_ICONINFORMATION |
An icon consisting of a lowercase letter i in a circle appears in the message box. |
| MB_ICONEXCLAMATION MB_ICONWARNING |
An exclamation-point icon appears in the message box. |
| MB_ICONERROR MB_ICONHAND MB_ICONSTOP |
A stop-sign icon appears in the message box. |
| MB_ICONQUESTION | A question-mark icon appears in the message box. |
| Window styles | |
| 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 message box's parent window are automatically disabled, but pop-up windows are not. MB_APPLMODAL is the default value. Windows CE does not support either MB_SYSTEMMODAL or MB_TASKMODAL. |
| MB_SETFOREGROUND | The message box becomes the foreground window. |
| MB_TOPMOST | The message box is created with the WS_EX_TOPMOST window style. |