WindowsFromDc返回null [英] WindowsFromDc return null

问题描述

我需要有关win32 api的帮助，尤其是WindowsFromDc.

I need some help about the win32 api and especially WindowsFromDc.

我有一个可以挂接到另一个应用程序的应用程序.这两个应用程序通过NamedPipe进行通信.在第二个应用程序中，我已钩住DrawTextExW函数，并从该函数获得了HDC.

I have a application which hook a another application. This two application communicate by a NamedPipe. In the second application, I have hook the DrawTextExW function and I get a HDC from this function.

但是当我使用DrawTextEx函数返回的DC执行WindowsFromDC时，我得到了空返回.

But when I do a WindowsFromDC with the DC returned by the DrawTextEx function, i got a null return.

因此，我对此有一些疑问: -HDC可能没有HDWN吗? -如何获取调用DrawTextEx的窗口的HWND?还有其他方法吗?

So, I have some question about that : -Is it possible a HDC don't have a HDWN with ? -How I can get the HWND of the window which call DrawTextEx ? There are other way do to that ?

谢谢.

Ps:对不起，我的英语不好...

Ps : Sorry for my bad english...

推荐答案

在跨进程传递时，设备上下文句柄无效.因此，您尝试做的事情是不可能的.

Device context handles are not valid when passed cross-process. So what you are attempting to do is not possible.

关于您的其他问题:

是否有可能没有与HWND关联的HDC?

是的，这完全有可能.大量的设备上下文与Windows无关.

Yes that is perfectly possible. Plenty of device contexts are not associated with windows.

如何获取调用DrawTextEx的窗口的HWND?

Windows不调用函数，而代码调用函数.因此，这个问题实际上没有任何意义.

Windows do not call functions, code calls functions. So, the question does not really mean anything.

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