COM中的IDispatch和IUnkown有什么区别？ [英] What is the difference between IDispatch and IUnkown in COM?

问题描述

我已经阅读并看到了 COM 的示例，但是我不能清楚地看到 Interface 之间的区别。

I have read and saw example for COM, but I couldn't clearly get there Interface difference.

推荐答案

IUnknown 是主要的COM接口。它提供了将COM对象的实例投射到其任何受支持的接口（QueryInterface）的基本能力。

IUnknown is the primal COM interface. It provides the basic ability to "cast" a instance of a COM object to any of it's supported interfaces (QueryInterface).

IDispatch IUnknown添加了在运行时发现指定COM对象支持的属性和接口的工具。这允许后期绑定和动态绑定。各种补救措施。借助IDispatch，应用程序可以发现组件的功能并调用发现的方法（简称为自动化）。

IDispatch builds on IUnknown adding the facility to discover at run-time the attributes and interfaces supported by the specified COM object. This allows for late-binding and dynamic-binding. A remedial reflection of sorts. With IDispatch, an application can discover the capability of components and invoke discovered methods (which was simplistically called automation).

请参见在MSDN上实现IDispatch接口[自动化] （从WayBack Machine复活-当前在线版本）。

See Implementing the IDispatch Interface [Automation] on MSDN (resurrected from WayBack Machine - current online version).

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