ActiveX Control Introduction

 

　　ActiveX is a new term that emerged when M $ fought against JAVA (March 1996 ), the predecessor of ActiveX technology is OLE technology, which is M $. To adapt to the development of the Internet, OLE is extended ("Activeate the Internet "), at that time, it was just to develop a small reusable component that can be quickly downloaded from the network. However, with the development of ActiveX technology, ActiveX soon became the new slogan of M $. ActiveX evolved from defining all content from WEB pages to OLE controls to defining a reusable component technology specification. ActiveX has become a concept and trend.

　　ActiveX is based on OLE and COM, but the various development tools of M $ can shield many technical details that are confusing in the COM model. This section mainly discusses how to develop ActiveX controls. In fact, this is only part of AcitveX component technology. ActiveX component technology includes the following aspects:

• Automated Server
• Automatic Controller
• Widget
• COM Object
• Document
• Container

The currentActiveX control is equivalent to the previous OLE control or OCX. A typical control includes the user interface during design and runtime. The unique IDispatch interface defines the properties and methods of the control, the unique IConnectionPoint interface defines events that can be triggered by controls. A control can be run in a container, so it is similar to a DLL in terms of running. Since the control support is added to IE, you can use VBScript to manipulate the control on the WEB page.

In additionCOM components are Binary compatible, when the code of one of the components is modified and the connection is re-compiled, as long as the existing and used interfaces remain unchanged (Other interfaces can be added) other files using this component do not need to be recompiled. Therefore, the use of COM component technology can greatly improve software reusability. If ActiveX controls are used in the program, you can upgrade the control independently without upgrading the entire program. While providing flexibility, it will lead to performance sacrifices, but it seems that these sacrifices are nothing to do with the benefits of ActiveX for our code.