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- IDispatch is the interface that exposes the OLE Automation protocol. Extending IUnknown, it is one of the standard interfaces that can be exposed by COM objects. COM distinguishes between three interface types: custom that are VTABLE-based IUnknown interfaces, dispatch that are IDispatch interfaces supporting introspection, and dual interfaces supporting both types. The Automation (IDispatch) interface allows a client application to find out what properties and methods are supported by an object at run-time, i.e. implements the concept of RTTI. It also provides the information necessary to invoke these properties and methods. Client applications do not need to be aware of the object members when they are compiled. This allows COM and ActiveX objects to be called by scripting programs platforms such as the ASP server and JavaScript on Internet Explorer, where calling conventions were not known at the time IIS or IE were built. By contrast, a simple object library is compiled and linked into a program, e.g. a DLL call needs to know a function name and parameters at compile time. A script writer can ask the COM object for a method or property it already knows about from documentation. Then, the client can execute the function with Invoke provided by the IDispatch interface, a form of late-binding. This sort of capability was also supported by Dynamic Data Exchange (DDE), which never became popular due to being too low-level. Dispatch interfaces are flexible, but suffer from additional introspection and invocation overhead compared to custom interfaces. It is therefore often a good idea to support both interface types with dual interfaces. That way, clients supporting VTABLE-based invocation can use the custom interface instead of the dispatch counterpart. (en)
- IDispatch介面是组件对象模型（COM）中的标准介面，也称自动化（Automation）接口，继承自IUnknown，用于讓其他函式使用协议。COM規格書規定COM物件应该是三种接口类型中的至少一种：
* 基于虚表（vtable）的IUnknown的定制接口；
* 分派（dispatch）的IDispatch接口以支持內觀資訊（introspection）。允许客户应用程序在运行时查出COM组件支持哪些属性与方法，即实现了运行期类型信息（RTTI）。客户应用程序编译时不需要知道COM的对象成员。脚本语言如VBS不能使用指针乃至函数指针，只能通过IDispatch接口访问COM组件。这是通过执行IDispatch接口中的Invoke方法。这是一种。与第一种定制接口相比，增加了內觀資訊与invoke的开销。
* dual接口，同时支持上述两种类型的接口 (zh)
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- 4490 (xsd:nonNegativeInteger)
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- IDispatch介面是组件对象模型（COM）中的标准介面，也称自动化（Automation）接口，继承自IUnknown，用于讓其他函式使用协议。COM規格書規定COM物件应该是三种接口类型中的至少一种：
* 基于虚表（vtable）的IUnknown的定制接口；
* 分派（dispatch）的IDispatch接口以支持內觀資訊（introspection）。允许客户应用程序在运行时查出COM组件支持哪些属性与方法，即实现了运行期类型信息（RTTI）。客户应用程序编译时不需要知道COM的对象成员。脚本语言如VBS不能使用指针乃至函数指针，只能通过IDispatch接口访问COM组件。这是通过执行IDispatch接口中的Invoke方法。这是一种。与第一种定制接口相比，增加了內觀資訊与invoke的开销。
* dual接口，同时支持上述两种类型的接口 (zh)
- IDispatch is the interface that exposes the OLE Automation protocol. Extending IUnknown, it is one of the standard interfaces that can be exposed by COM objects. COM distinguishes between three interface types: custom that are VTABLE-based IUnknown interfaces, dispatch that are IDispatch interfaces supporting introspection, and dual interfaces supporting both types. (en)
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- IDispatch (en)
- IDispatch (zh)
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