.OCX ファイル拡張子

An OCX file is an ActiveX Control file that can be embedded into Microsoft applications. These control files are used to add custom features and functionalities to an app that it might not have in its out-of-the-box form and to create toolbar gadgets and other forms of customizations in Windows applications.

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Windows includes many ActiveX controls, while software installers share others. For a software app to use ActiveX control, it must first be registered in Windows. As such, many installers include the registration step as part of their installation process.

Software developers use specific tools for creating ActiveX controls. When they package a control, they define properties and methods that conform to Microsoft's Component Object Model specification. Once the definition is created, other software apps can access the packaged control if the developer first registers it with Windows.

While most developers no longer use ActiveX for creating software components, these modules are still supported in Windows 10 via Internet Explorer 11 and can be registered manually.