在不修改接口的情况下，将delphi接口转换为实现类 [英] Casting a delphi interface to its implementation class without modifying the interface

问题描述

可能重复：

如何在Delphi中将接口转换为对象

使用Delphi 5;我有一个接口，我不能因为遗留原因而改变。我正在传递（指向），界面遍布整个地方。实现类有几个新属性 - 有没有办法强制从接口到实际执行的转换？

Using Delphi 5; I have an interface that I cannot change for legacy reasons. I am passing (pointers to) that interface all over the place. The implementing class has several new properties - is there a way to force a cast from the interface to the actual implementation?

http://www.malcolmgroves.com/blog/?p=500 说，这是（新）在Delphi 2010中实现的，其中强烈建议以前是不可能的。确实是这样，还是有一种我不熟悉的方式？ RTTI，可能吗？

http://www.malcolmgroves.com/blog/?p=500 says that this is (newly) implemented in Delphi 2010, which strongly suggest that it wasn't possible before. Is this indeed the case, or is there a way I'm not familiar with? RTTI, maybe?

（我检查了，如果pScore是TOleScore，那么确实不允许Delphi 5编译器 - 这里 pScore 是我的 pScore：IScore 参数和 TOleScore 是实现类。）

(I checked, and if pScore is TOleScore then is indeed not allowed by the Delphi 5 compiler - here pScore is my pScore: IScore argument, and TOleScore is the implementing class.)

推荐答案

• 经典的作品是由Hallvard Vassbotn： Hack＃7：Object to Object


• 最近，Delphi编译工程师Barry Kelly也提供了一个实现：对象转换接口的一个难看的替代方法


• The classic take on this is by Hallvard Vassbotn: Hack #7: Interface to Object
• More recently Barry Kelly, a Delphi compiler engineer, also provided an implementation: An ugly alternative to interface to object casting

我认为这两种方法都可以正常工作。

I think both approaches should work.

有没有人知道哈佛是否仍然活跃？过去几年我没有碰到过他。

Incidentally, does anyone know if Hallvard is still active? I've not come across him in the past few years.

这篇关于在不修改接口的情况下，将delphi接口转换为实现类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！