Alison Balteramp;#039;s Mastering Microsoft Office Access 1002003 [Electronic resources] نسخه متنی

Why This Chapter Is Important

A powerful aspect of Access 2003 is its extensibility. In addition to the controls available as part of the product, you can incorporate ActiveX controls on your forms. This means that you aren't limited by what Access supplies, only by the imaginations of third-party developers who design ActiveX controls.

NOTE

Several years ago, Microsoft renamed

OLE

controls to

ActiveX controls . You will still sometimes see these terms used interchangeably. In this book, I refer to them as ActiveX controls.

ActiveX controls support the OLE 2.0 custom control architecture and provide support for 32-bit operating systems. They have their own code, methods, events, and properties. An ActiveX control's functionality is stored in a file with an .ocx extension. This is why ActiveX controls are often referred to as OCXs. A Calendar OCX control comes with Microsoft Access. Additional OCX controls are available as part of Windows, or from third-party vendors such as FMS, DBI Technologies, Database Creations, Crescent, Sheridan, Far Point, and many others.

Two types of ActiveX controls exist. The first is visible at both design time and runtime; after being placed on a form, it provides a front-end interface that allows the user to directly manipulate the object. One example is the Calendar control in Access 2003. The second type of ActiveX control is visible at design time, but not at runtime; this type of control can, for example, give you access to all Windows common dialog boxes, such as Open, Print, and so on. The control itself isn't visible to the user, but its functionality is available to the user at runtime. An example of this type of control is the Timer control; it operates within the application, triggering event code to run, but it isn't actually visible to the user.

With ActiveX controls, you can easily incorporate more functionality into your applications. For example, if you need to include a calendar on your form, you don't need to worry about how to build your own. Instead, you can include a custom Calendar control and modify the calendar's behavior by changing its properties and executing its methods.