ActiveX Controls

How does a container bring control class code (binary executable code) into memory and instantiate a control of that class?

There is no question that OLE Controls, or Component Object Model (COM) objects in general, are useful as part of a document or page on an Internet site. However, some problems exist with regard to how a control is specified within a document, and how a control can behave well in a slow-link environment such as the Internet, including how the control retrieves its data in an incremental or progressive fashion, working well with other controls that might also be retrieving their data in the same manner.

The following table summarizes the added standard dispIDs described in this article.

For all persistence interfaces other than IPersistMoniker, the authoring tool or container assumes that once IPersist*::Load returns, the control has loaded all its properties. However, controls that use data paths might not actually have all of their data at this time.

This article is, however, concerned with the more general problem of retrieving any significant amounts of data in a cooperative fashion from possibly many distributed locations after the control has already been instantiated and is possibly interacting with the container and the user in other ways. This capability has been called "Progressive Rendering," "Progressive Property Disclosure," and "Progressive Downloading." The term "Progressive Data Retrieval" will be used to refer to all of these more special cases at once, because it makes no assumptions about the exact type of data that is being retrieved—for example, it might be properties, might be images, might be anything.

This topic describes how to register a ActiveX object as the viewer or player for a particular media type (MIME). This registration is essential for Internet Explorer to launch the correct player when interpreting the standard HTML A HREF tag or the Netscape-introduced EMBED tag. Without this registration, it is impossible for Internet Explorer to guess what application to use to display or play an unknown media file.

This article is an overview for ActiveX control containers. The following sections explain how to implement and program ActiveX control containers that will function well with other controls and containers.

This article explains the licensing strategy for ActiveX controls. In addition, it describes the functionality that must be implemented on an ActiveX control in order to support this strategy.

For many existing and future ActiveX controls, Windows Internet Explorer 8 removes administrative involvement from the installation process. The solution addresses issues raised by enterprise customers who used previous versions of Windows Internet Explorer, where administration of controls was not optimal. Non-administrative ActiveX controls (or per-user ActiveX installation) is available on Windows Vista and later.

This document describes palette management for ActiveX objects, specifically ActiveX Controls and Active Document objects. The palette management rules described herein allow multiple controls inside a form or an HTML page to display correctly, while still leaving enough flexibility to allow a control to demand palette control. In general, containers are responsible for palette management, and contained objects (for example, controls) should only realize their palettes in the background.

This article describes the code that a control developer should implement to ensure safe initialization and safe scripting for a ActiveX control.

As a benefit to control developers, Microsoft will supply Internet-aware picture, sound, and video objects that will make dealing with these data formats in the Internet environment a non-issue for many controls. The existing picture object, for example, makes a control's manipulation of a bitmap, metafile, or icon nearly effortless. The additional objects described here aim to do the same for their respective data types, where all standard objects will support the ability to retrieve large data BLOBs in an asynchronous manner.

This article describes the API elements that enable third-party developers to hook into the offline browsing architecture. It also provides some recommendations to help developers provide a seamless experience for users.