The structure of your application remains the same as when using a dialog box that does not contain an ActiveX control. SeeWriting a Dialog Applicationfor details. This section discusses programming specific to ActiveX controls.
Your application must callCOMINITIALIZEbefore callingDLGINITwith a dialog box that contains an ActiveX control. Your application must include the statementUSE IFCOMto access COMINITIALIZE. Your application must callCOMUNINITIALIZEwhen you are done using ActiveX controls, but not before callingDLGUNINITfor the dialog box that contains the ActiveX control.
You can call the methods of an ActiveX control and set and retrieve its property values using the interfaces generated by the Intel Fortran Module Wizard or by using the IFAUTO routines. To do this, you must have the object's IDispatch interface pointer. Use theDLGGETfunction with the ActiveX control's name, the DLG_IDISPATCH control index, and an integer variable to receive the IDispatch pointer. For example:
retlog = DlgGet( dlg, IDC_ACTIVEX, idispatch, DLG_IDISPATCH )
You do not need to specify the index DLG_IDISPATCH because it is the default integer index for an ActiveX control.
However, the control's IDispatch pointer is not available until after the control has been created and is only valid until the dialog box is closed. The control is created during the call toDLGMODALDLGMODELESSor . If you call DLGGETto retrieve the IDispatch pointer before callingDLGMODAL orDLGMODELESS, the value returned will be 0.
Do not callCOMRELEASEOBJECTwith the iDispatch pointer returned byDLGGET. The dialog procedures use a reference counting optimization since the lifetime of the control is guaranteed to be less than the lifetime of the dialog box.
If you want to use a method or property of a control before the dialog box is displayed to your application's user, you can use a DLG_INIT callback. CallDLGSETSUBusing the dialog box name and the DLG_INIT index to define the callback. For example:
retlog = DlgSetSub( dlg, IDD_DIALOG, DlgSub, DLG_INIT )
The DLG_INIT callback is called after the dialog box is created but before it is displayed (with
callbacktype=DLG_INIT) and immediately before the dialog box is destroyed (with callbacktype=DLG_DESTROY). The DLG_INIT callback is the soonest that the control's IDispatch pointer is available. The DLG_DESTROY callback is the latest that this pointer is valid. After the DLG_DESTROY callback, the ActiveX control is destroyed. The following example shows using aDLG_INITcallback to reset the state of a control property before it is destroyed:
SUBROUTINE mmplayerSub( dlg, id, callbacktype ) !DEC$ ATTRIBUTES DEFAULT :: mmplayerSub use iflogm
use ifcom use ifauto implicit none type (dialog) dlg integer id, callbacktype include 'resource.fd' integer obj, iret logical lret
if (callbacktype == dlg_init) then
lret = DlgGet(dlg, IDC_ACTIVEMOVIECONTROL1, obj) ! Add any method or property calls here before the ! dialog box is displayed
else if (callbacktype == dlg_destroy) then
! Reset the filename to "" to "close" the current file lret = DlgGet(dlg, IDC_ACTIVEMOVIECONTROL1, obj) iret = AUTOSETPROPERTY(obj, "FileName", "") endif
END SUBROUTINE mmplayerSub
The module generated by the Fortran Module Wizard for an ActiveX control contains a number of sections:
•
! CLSIDsParameters of derived type GUID which identify the ActiveX control class. Your application typically doesn't need to use this parameter.
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! IIDsParameters of derived type GUID which identify source (event) interfaces of the ActiveX control. Your application can use these values in calls to DLGSETCTRLEVENTHANDLER (see below).
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! EnumsParameters of type integer that identify constants used in the ActiveX control's interfaces.
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! InterfacesInterfaces for the source (event) interfaces that are defined by the ActiveX control. There may be 0, 1, or more source interfaces implemented by the control. A control does not have to support events.
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! Module ProceduresSee the Language Reference for more information on using the method and property interfaces generated by the Intel Fortran Module Wizard.
In addition to methods and properties, ActiveX controls also define events to notify your application that something has happened to the control. The dialog procedures provide a routine,DLGSETCTRLEVENTHANDLER, that allows you to define a routine to be executed when an event occurs.
TheDLGSETCTRLEVENTHANDLERfunction has the following interface: integer DlgSetCtrlEventHandler( dlg, controlid, handler, dispid, iid ) The arguments are as follows:
(Input) Derived type DIALOG. Contains dialog box parameters. dlg
(Input) Integer. Specifies the identifier of a control within the dialog box (from the .FD file). controlid
(Input) EXTERNAL. Name of the routine to be called when the event occurs. handler
(Input) Integer. Specifies the member id of the method in the event interface that identifies the event
dispid
(Input, Optional) Derived type (GUID). Specifies the Interface identifier of the source (event) interface. If not supplied, the default source interface of the ActiveX control is used.
iid
Consider the following function call:
ret = DlgSetCtrlEventHandler( dlg, IDC_ACTIVEMOVIECONTROL1, & ActiveMovie_ReadyStateChange, -609, IID_DActiveMovieEvents2 ) In this function call:
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IDC_ACTIVEMOVIECONTROL1identifies an ActiveMovie control in the dialog box.•
ActiveMovie_ReadyStateChangeis the name of the event handling routine.•
-609is the member id of the ActiveMovie's control ReadyStateChange event. You can get this number from: • The module that the Fortran Module Wizard generated. There is a "MEMBERID = nn" comment generatedfor each method in a source interface (see the example below). • The documentation of the ActiveX control.
• A tool that allows you to examine the type information of the ActiveX control, for example, the OLE/COM Object Viewer in the Microsoft Visual Studio* IDE.
•
IID_DActiveMovieEvents2is the identifier of the source (event) interface.The interface generated by the Intel Fortran Module Wizard for the ReadyStateChange event follows: INTERFACE
!Reports that the ReadyState property of the ActiveMovie Control !has changed
! MEMBERID = -609
SUBROUTINE DActiveMovieEvents2_ReadyStateChange($OBJECT, ReadyState) INTEGER(4), INTENT(IN) :: $OBJECT ! Object Pointer
!DEC$ ATTRIBUTES VALUE :: $OBJECT INTEGER(4) :: ReadyState
!DEC$ ATTRIBUTES VALUE :: ReadyState
!DEC$ ATTRIBUTES STDCALL :: DActiveMovieEvents2_ReadyStateChange END SUBROUTINE DActiveMovieEvents2_ReadyStateChange
The handler that you define in your application must have the same interface. Otherwise, your application will likely crash in unexpected ways because of the application's stack getting corrupted.
Note that an object is always the first parameter in an event handler. This object value is a pointer to the control's source (event) interface, not the IDispatch pointer of the control. You can useDLGGETas described above to retrieve the control's IDispatch pointer.