What Is a Component Object Model?

Component Object Model (COM) is a set of component object interface standards based on the Windows platform. It consists of a set of construction specifications and a component object library. General objects are composed of data members and methods acting on them, while component objects and general objects are similar, but they are quite different. Component objects use interfaces instead of methods to describe themselves. An interface is defined as "a set of semantically related functions implemented on an object". Its essence is a set of function pointer tables. Each pointer must be initialized to point to a specific function body. There is no limit to the number of interfaces that a component object implements. ^[1]

Component Object Model

COM is a component software platform proposed by Microsoft since 1993.

COM is designed based on the concept of component object approach. In the foundation, at least each component can support two functions:

• Querying which interfaces are in the component (User Interface)

• Let components do self-life management, the practice of this concept is

  COM was the main software development platform under the Windows platform, and it affected many other related software technologies.

  COM +

  COM + is an enhanced implementation of Microsoft Transaction Server in Microsoft Windows 2000. In addition to providing basic component transaction support, it also provides application servers for loosely-coupled events and object pooling. Capabilities, became the main application server platform on the Microsoft platform starting with Windows 2000. At present, the .NET Framework also provides the System.EnterpriseServices namespace to support COM +.

  Distributed COM

  Distributed COM is a COM component that can communicate on the network. It is developed according to the RPC (Remote Procedure Call) specification. It extends the capabilities of the COM component to the network, but because of network security and firewall issues, the device context is Cannot be widely spread.

  .NET

  .NET Framework is a new generation of Microsoft Windows application development platform.