The INSTALLUI_HANDLER function prototype defines a callback function that the installer calls for progress notification and error messages. For more information on the usage of this function prototype, a sample code snippet is available in Handling Progress Messages Using MsiSetExternalUI.

Syntax

C++INT CALLBACK InstalluiHandler(
    LPVOID pvContext,
    UINT iMessageType,
    LPCTSTR szMessage
);

Parameters

pvContext

Pointer to an application context passed to the MsiSetExternalUI function. This parameter can be used for error checking.

iMessageType

Specifies a combination of one message box style, one message box icon type, one default button, and one installation message type. This parameter must be one of the following.

Message box StylesFlag	Meaning
MB_ABORTRETRYIGNORE	The message box contains the Abort, Retry, and Ignore buttons.
MB_OK	The message box contains the OK button. This is the default.
MB_OKCANCEL	The message box contains the OK and Cancel buttons.
MB_RETRYCANCEL	The message box contains the Retry and Cancel buttons.
MB_YESNO	The message box contains the Yes and No buttons.
MB_YESNOCANCEL	The message box contains the Yes, No, and Cancel buttons.

 

Message box IconTypesFlag	Meaning
MB_ICONEXCLAMATION, MB_ICONWARNING	An exclamation point appears in the message box.
MB_ICONINFORMATION, MB_ICONASTERISK	The information sign appears in the message box.
MB_ICONQUESTION	A question mark appears in the message box.
MB_ICONSTOP, MB_ICONERROR, MB_ICONHAND	A stop sign appears in the message box.

 

Default ButtonsFlag	Meaning
MB_DEFBUTTON1	The first button is the default button.
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.

 

Install message TypesFlag	Meaning
INSTALLMESSAGE_FATALEXIT	Premature termination
INSTALLMESSAGE_ERROR	Formatted error message
INSTALLMESSAGE_WARNING	Formatted warning message
INSTALLMESSAGE_USER	User request message.
INSTALLMESSAGE_INFO	Informative message for log
INSTALLMESSAGE_FILESINUSE	List of files currently in use that must be closed before being replaced.
INSTALLMESSAGE_RESOLVESOURCE	Request to determine a valid source location
INSTALLMESSAGE_RMFILESINUSE	List of files currently in use that must be closed before being replaced. Available beginning with Windows Installer 4.0. For more information about this message see Using Restart Manager with an External UI.
INSTALLMESSAGE_OUTOFDISKSPACE	Insufficient disk space message
INSTALLMESSAGE_ACTIONSTART	Start of action message. This message includes the action name and description.
INSTALLMESSAGE_ACTIONDATA	Formatted data associated with the individual action item.
INSTALLMESSAGE_PROGRESS	Progress gauge information. This message includes information on units so far and total number of units.
INSTALLMESSAGE_COMMONDATA	Formatted dialog information for user interface.
INSTALLMESSAGE_INITIALIZE	Sent prior to UI initialization, no string data
INSTALLMESSAGE_TERMINATE	Sent after UI termination, no string data
INSTALLMESSAGE_SHOWDIALOG	Sent prior to display of authored dialog or wizard
INSTALLMESSAGE_INSTALLSTART	Sent prior to installation of product.
INSTALLMESSAGE_INSTALLEND	Sent after installation of product.

 

The following defaults should be used if any of the preceding messages are missing: MB_OK, no icon, and MB_DEFBUTTON1. There is no default installation message type; a message type is always specified.

szMessage

Specifies the message text.

Return Value

-1

An error was found in the message handler. Windows Installer ignores this returned value.

0

No action was taken.

The following return values map to the buttons specified by the message box style:

IDOK
IDCANCEL
IDABORT
IDRETRY
IDIGNORE
IDYES
IDNO

Remarks

For more information on returning values from an external user interface handler, see the Returning Values from an External User Interface Handler topic.

Requirements

Version	Windows Installer 5.0 on Windows Server 2008 R2 or Windows 7. Windows Installer 4.0 or Windows Installer 4.5 on Windows Server 2008 or Windows Vista. Windows Installer on Windows Server 2003, Windows XP, and Windows 2000
Header	Msi.h
Unicode and ANSI names	INSTALLUI_HANDLERW (Unicode) and INSTALLUI_HANDLERA (ANSI)

See Also

MsiSetExternalUI

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Build date: 8/13/2009