Class XbpActiveXControl() Foundation

The class XbpActiveXControl implements a generic control container for hosting ActiveX controls. Xbase++ applications use instances of the XbpActiveXControl class to integrate ActiveX controls with their user interface and to interact with the control through the methods and instance variables introduced by this class.

An ActiveX control is an automation object that implements a windowed user interface component. An ActiveX control is roughly comparable to an Xbase Part in that it contains logic to display a visual representation and defines interfaces for communicating with the Xbase++ application. However, an ActiveX control is not created directly. Instead, the control's life cycle is managed implicitly by the automation server that exposes the interfaces of the ActiveX control.

XbpActiveXControl uses the functionality inherited from class AutomationObject to create and manage an ActiveX control requested by an Xbase++ application. Also, the class builds on the event handling mechanism introduced by its base class ActiveXObject. Internally, XbpActiveXControl implements COM interfaces required for hosting the control and maintaining its display area. Please see the documentation on class AutomationObject to learn more about automation objects and COM/ActiveX interfaces.

From the perspective of the Xbase++ application, an ActiveX control hosted by an XbpActiveXControl object behaves like a normal Xbase Part. The application communicates with the control by setting instance variables or calling methods on the XbpActiveXControl instance.

Specifically, the class XbpActiveXControl implements the following functionality:

Using an ActiveX Control

// 
// Create a label control as a child of an 
// existing dialog. The example uses 
// a Presentation Parameter to defines the 
// label control's background color 
// 
aPP := { {XBP_PP_BGCLR, GRA_CLR_RED} } 
oLabel       := XbpActiveXControl():new( oDlg:drawingArea,{10,250},{100,80} ) 
oLabel:CLSID := "Forms.Label" 
oLabel:create( oDlg:drawingarea,,,aPP,.F.) 

// 
// Assign a code block for handling "left 
// mouse button down" events and show 
// ActiveX control 
// 
oLabel:lbDown := {|| MsgBox("Label was clicked on!")} 
oLabel:show()