ActiveX Controls

1
ActiveX Controls

• What is Com and ActiveX
• How to create them
• How to install them

2
Component Object Model (COM)

• Object oriented modules and executables
• a binary specification
• programming language-independent
• VB, VBScript, C, Visual C, C, Java (?),
  Delphi
• can contain both data and functionality
• can only be accessed by a public interface

3
Component Object Model (COM)

• Several ways to package/access COM objects
• within a process (.dll)
• across processes (.exe)
• across machines/platforms (dcom)

4
You have seen COM before

• Origins
• OLE and OLE automation
• allows a client to call the services exposed by
  an application
• ActiveX
• renamed and updated COM technology
• usable over the Internet by Internet Explorer
• .Net
• revamped COM
• makes it accessible over the net
• Soap, XML, etc

5
ActiveX variations

• ActiveX dlls
• library components with no visual interface
• runs with a process
• VB Project/references

6
ActiveX variations

• ActiveX exes
• executable component
• server (e.g., database)
• major application (e.g., Word)
• services accessed through its COM interface
• VB
• CreateObject (class, serverName)

DCOM
Your program
Your program
Machine A
Machine A
Machine B
7
ActiveX variations

• ActiveX Control .ocx
• interactive object with a visual interface
• VB Project/Component
• example
• Microsoft Windows Common Controls 6.0

Your program
8
An ActiveX HelloWorld control

• See tutorial 5 in VB Examples