The MsiSetExternalUI function enables an external user-interface handler. This external UI handler is called before the normal internal user-interface handler. The external UI handler has the option to suppress the internal UI by returning a non-zero value to indicate that it has handled the messages. For more information, see About the User Interface.

Syntax

INSTALLUI_HANDLER MsiSetExternalUI(
  __in  INSTALLUI_HANDLER puiHandler,
  __in  DWORD dwMessageFilter,
  __in  LPVOID pvContext
);

Parameters

puiHandler [in]

Specifies a callback function that conforms to the INSTALLUI_HANDLER specification.

dwMessageFilter [in]

Specifies which messages to handle using the external message handler. If the external handler returns a non-zero result, then that message will not be sent to the UI, instead the message will be logged if logging has been enabled. For more information, see the MsiEnableLog function.

Value	Meaning
INSTALLLOGMODE_FILESINUSE	Files in use information. When this message is received, a FilesInUse Dialog should be displayed.
INSTALLLOGMODE_FATALEXIT	Premature termination of installation.
INSTALLLOGMODE_ERROR	The error messages are logged.
INSTALLLOGMODE_WARNING	The warning messages are logged.
INSTALLLOGMODE_USER	The user requests are logged.
INSTALLLOGMODE_INFO	The status messages that are not displayed are logged.
INSTALLLOGMODE_RESOLVESOURCE	Request to determine a valid source location.
INSTALLLOGMODE_RMFILESINUSE	Files in use information. When this message is received, a MsiRMFilesInUse Dialog should be displayed.
INSTALLLOGMODE_OUTOFDISKSPACE	There was insufficient disk space.
INSTALLLOGMODE_ACTIONSTART	The start of new installation actions are logged.
INSTALLLOGMODE_ACTIONDATA	The data record with the installation action is logged.
INSTALLLOGMODE_COMMONDATA	The parameters for user-interface initialization are logged.
INSTALLLOGMODE_PROGRESS	Progress bar information. This message includes information on units so far and total number of units. For an explanation of the message format, see the MsiProcessMessage function. This message is only sent to an external user interface and is not logged.
INSTALLLOGMODE_INITIALIZE	If this is not a quiet installation, then the basic UI has been initialized. If this is a full UI installation, the full UI is not yet initialized. This message is only sent to an external user interface and is not logged.
INSTALLLOGMODE_TERMINATE	If a full UI is being used, the full UI has ended. If this is not a quiet installation, the basic UI has not yet ended. This message is only sent to an external user interface and is not logged.
INSTALLLOGMODE_SHOWDIALOG	Sent prior to display of the full UI dialog. This message is only sent to an external user interface and is not logged.
INSTALLLOGMODE_INSTALLSTART	Installation of product begins. The message contains the product's ProductName and ProductCode.
INSTALLLOGMODE_INSTALLEND	Installation of product ends. The message contains the product's ProductName, ProductCode, and return value.

pvContext [in]

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

Return Value

The return value is the previously set external handler, or zero (0) if there was no previously set handler.

Remarks

To restore the previous UI handler, second call is made to MsiSetExternalUI using the INSTALLUI_HANDLER returned by the first call to MsiSetExternalUI and specifying zero (0) for dwMessageFilter.

The external user interface handler pointed to by the puiHandler parameter does not have full control over the external user interface unless MsiSetInternalUI is called with the dwUILevel parameter set to INSTALLUILEVEL_NONE. If MsiSetInternalUI is not called, the internal user interface level defaults to INSTALLUILEVEL_BASIC. As a result, any message not handled by the external user interface handler is handled by Windows Installer. The initial "Preparing to install. . ." dialog always appears even if the external user interface handler handles all messages.

MsiSetExternalUI should only be called from a Bootstrapping application. You cannot call MsiSetExternalUI from a custom action.

Requirements

See Also

Interface and Logging Functions

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Build date: 6/5/2008