A Microsoft ActiveX control is essentially a simple OLE object that supports
the IUnknown
interface. This section offers solutions for making a control work well in the
Internet environment, with the ultimate goal of delivering optimal quality of
service to users. For example, because browser speed is one of the primary
factors in users' perception of quality, this section aims to provide solutions
that allow an HTML document or page to become visible as soon as possible and
interactive very shortly thereafter, while allowing controls to retrieve large
data blocks in the background.
About
ActiveX Controls
This section introduces ActiveX Controls and provides general guidelines
for control developers. It includes information about run-time licensing for
an ActiveX control, identifying an ActiveX control as safe for scripting or
safe for code download, packaging an ActiveX control in a .cab file, and
applying a test certificate to an ActiveX control.
About
Control Instantiation
How does a container bring control class code (binary executable code) into
memory and instantiate a control of that class?
About
Cooperative and Asynchronous Data Retrieval
To deliver optimal quality of service to browser users, a control must read
data from an external source in a cooperative manner as much as possible. That
is, the control should support reading linked data in an asynchronous manner,
paying attention to container prioritization and allowing the container to
participate in the transfer as it wants. To provide the container with
authority over the binding operation, the control should use the IBindHost::MonikerBindToStorage
and IBindHost::MonikerBindToObject
methods to bind to any moniker.
About
Internet COM Object Requirements
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.
About
IObject Safety Extensions for Internet Explorer
This document describes the extensions to the IObjectSafety
interface that support the new security features implemented in Microsoft
Internet Explorer 4.0.
Added
Standard Properties, Methods, Events, and Interfaces
The following table summarizes the added standard dispIDs described in this
article.
Building
ActiveX Controls for Internet Explorer
This article covers features of Windows Internet Explorer that a developer
writing ActiveX Controls should take into account when targeting Internet
Explorer as a container. Some of the material in this article discusses
existing technologies that have increased relevance with Internet Explorer;
other sections discuss new technologies and services that are available only
to a control in Internet Explorer.
Communicating
Control Readiness
For all persistence interfaces other than IPersistMoniker,
the authoring tool or container assumes that once IPersist*::Load .gif)
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.
Component
Categories for Describing Internet-Aware Objects
A category identifier (CATID) is a GUID that is stored in the registry as
an attribute of a class. There are various useful categories for introducing a
ActiveX control to its container; they describe which features the object
requires and those it implements.
Data Path
Properties
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.
Designing
Secure ActiveX Controls
Any ActiveX control should be conceived and designed with security in
mind.
How to
Register an ActiveX Object as the Player for a Media Type
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.
Internet
Awareness for Objects, Controls, and Containers
The following documents, which are referenced in text using shortened
names, contain information relevant to COM objects.
Introduction
to ActiveX Control Containers
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.
Introduction
to ActiveX Controls
The purpose of this topic is to provide guidelines for implementing ActiveX
Controls that interoperate well with containers and other controls. This
article defines the minimum set of interfaces, methods, and features that are
required of ActiveX Controls to accomplish seamless and useful
interoperability.
Licensing
ActiveX Controls
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.
Managing
ActiveX Control Loading
Like other software programs, ActiveX controls may contain vulnerabilities.
Loading vulnerable ActiveX controls into Internet Explorer can place your
computer at risk. This article shows how to prevent Internet Explorer from
loading vulnerable ActiveX controls. It also shows how to redirect such
requests to load alternate, more secure ActiveX controls.
Packaging
ActiveX Controls
This article introduces a data-compression technology and associated tool
set that you can use to package your ActiveX control for faster, more
efficient downloading over the Internet or an intranet.
Palette
Management for ActiveX Objects
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.
Safe
Initialization and Scripting for ActiveX Controls
This article describes the code that a control developer should implement
to ensure safe initialization and safe scripting for a ActiveX
control.
Security
Considerations: ActiveX
This document provides information about security considerations related to
ActiveX.
Standard
Internet-Aware Objects
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.
Storage of
Control Persistent Data
When a control has any persistent data at all, the class identifier (CLSID)
element always exists along with one or both of the other two elements. How
these elements are stored in relation to the container document involves the
concepts of embedding and linking, which originated in OLE Documents (the OLE
compound document architecture), described in a following section.
Supporting
Offline Browsing in Applications and Components
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.
Using
ActiveX Controls to Automate Your Web Pages
This article describes how a developer can add ActiveX support to an
existing OLE Automation control.