为什么必须密封WinRT类型? [英] Why do WinRT types have to be sealed?

问题描述

在多个地方(例如"创建MSDN上的C#和Visual Basic 中的用于JavaScript的Windows运行时组件")，我已经看到它指定，如果您要在.NET中编写要从JavaScript使用的类，则必须将其设置为密封类.

In several places (e.g. "Creating Windows Runtime Components for JavaScript, in C# and Visual Basic" on MSDN), I've seen it specified that, if you write a class in .NET that you want to use from JavaScript, then you must make it a sealed class.

这似乎是一个任意限制.为什么JavaScript只能与密封类一起使用?

This seems like an arbitrary restriction. Why can JavaScript only work with sealed classes?

推荐答案

从JavaScript的角度来看，暴露给JavaScript应用程序的Windows运行时对象是封闭的-您不能将expando属性添加到WinRT对象.但是从C ++和C#中，如果对象支持继承，则可以继承winrt对象(例如，大多数Xaml类支持继承，而大多数其他类则不支持).

Windows runtime objects exposed to JavaScript applications are sealed from a JavaScript perspective - you can't add expando properties to WinRT objects. But from C++ and C#, winrt objects can be inherited if the object supports inheritance (most Xaml classes support inheritance for instance, but most others don't).

将WinRT对象与JS隔离的原因是，无论应用程序执行了什么操作，都要确保Winrt对象的行为相同-如果应用程序在对象上重新定义了某些功能属性，则可能导致应用程序的其他部分行为不当.

The reason that WinRT objects are sealed from JS is to ensure that the winrt object behave the same regardless of what the app has done - if an app redefines some function property on an object, it could cause other parts of the app to misbehave.

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