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MessageBox.md

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Function name : MessageBox

Group: Dialog Box - Library: user32

Note that this document contains some links to the old news2news website which does not work at the moment. This material will be available sometime in the future.

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

Code examples:

Using the MessageBox Win32 function
How to change the name and the size of the font in the MessageBox dialog
How to display a user-defined icon in the MessageBox dialog

Declaration:

int MessageBox(
  HWND hWnd,          // handle to owner window
  LPCTSTR lpText,     // text in message box
  LPCTSTR lpCaption,  // message box title
  UINT uType          // message box style
);

FoxPro declaration:

DECLARE INTEGER MessageBox IN user32 As MessageBoxA;
	INTEGER hwnd,;
	STRING  lpText,;
	STRING  lpCaption,;
	INTEGER wType

Parameters:

hWnd [in] Handle to the owner window of the message box to be created

lpText [in] Pointer to a null-terminated string that contains the message to be displayed

lpCaption [in] Pointer to a null-terminated string that contains the dialog box title

uType [in] Specifies the contents and behavior of the dialog box. This parameter can be a combination of flags

Return value:

If the function succeeds, the return value is one of the predefined menu-item values

Comments:

See also: MessageBoxIndirect, TaskDialog, TaskDialogIndirect, SetWindowsHookEx.

Right-to-left MessageBox (see Usage code above):

Click on the picture below to download
Extended MessageBox library (FLL) for Visual FoxPro.

Download MsgBox FLL

The Visual FoxPro contains a limited edition of this function, which is implemented via MESSAGEBOX() function. In most of the cases that is enough. Through the Win32 function you can reach all functionality of this dialog box.

The VFP, up to the version 6, gives an access to three groups of constants defining the contents and behavior of this object. There are several more groups (see the examples), which could be helpful.

For example, you can create a message box, which is placed on top of all open windows, not only the FoxPro Main window. Some other combinations of constants can give even more functionality, just try.

Another application of this function you might be interested in is to invoke a dailog in Automation Servers (EXE, DLL or MTDLL) created with Visual FoxPro. Built-in MessageBox generates an error (or at least fails to appear) while the API version of this function works Ok.

There are so many interfaces to this simple function from various programming languages. Here is another one from the Windows Scripting with the Timeout parameter puzzlingly positioned at the second place:

Usage:

object.Popup (Message [, TimeOut][, Title] [, Format])
WshShell = CREATEOBJECT("WScript.Shell")  
Result = WshShell.Popup("This is a popup box!", 10, "Title", 65)  
? Result

An enhancement in the MessageBox implementation in Vista: the OS wraps long messages maintaining a reasonable width of the dialog window.

The SetWindowsHookEx, while virtually useless in pure VFP code, can easily be utillized in Visual FoxPro via creating a FLL or DLL library.

For example, provided a certain windows hook set, each following MESSAGEBOX() dialog within current VFP session would appear not centered but instead would automatically position itself at the specified screen location.