C ++ / CLI：Public ref struct生成C2011：'class'type redefinition [英] C++/CLI: Public ref struct generates C2011: 'class' type redefinition

问题描述

我在托管的DLL项目中有一个头文件：

I have a header file in a managed DLL project like so:

Enums.h：

#pragma once
...
public ref struct ManagedStruct {
    Bitmap^ image;
}
...

DLL和从单独的可执行文件。单独的托管结构正在生成：

This header is referenced both from another class in the DLL and from a separate executable. The managed struct alone is generating:

错误C2011：'ManagedStruct'：'类'类型重新定义

error C2011: 'ManagedStruct' : 'class' type redefinition.

如果我将结构移动到DLL中的主头文件，它工作正常，可以公开访问，这就是我在做什么，但我会非常喜欢了解为什么这种情况发生时，我只是把它移动到另一个文件。

If I move the struct to the main header file in the DLL it works fine, and is publicly accessible, so that's what I'm doing, but I would very much like to learn why this is happening when I just move it to another file.

我已经检查所有必要的包括和命名空间，尝试了明显的标题卫队，无效;我仍然得到错误。

I have checked all necessary includes and namespaces AND tried the obvious header guards, to no avail; I still get the error.

非常感谢任何洞察力。

推荐答案

您必须调整传统的C / C ++头文件，当您使用托管代码时，有点想。类型声明的主要来源是组件元数据。这与本地C / C ++编译模型非常不同，在本地C / C ++编译模型中，您可以具有一个头文件，用于其他模块可见的类型。

You have to de-tune the traditional C/C++ header file think a bit when you work with managed code. The principal source of type declarations is the assembly metadata. This is very different from the native C/C++ compilation model where you have to have a header file for types that you make visible to other modules.

我要猜测你在EXE项目中得到这个C2011错误。你在哪里都添加了一个对DLL项目组件的引用（就像你应该）和在头文件中使用#include。像你不应该。这是一个保证重复的定义，#pragma一次不能解决这个问题。

I'm going to guess that you get this C2011 error in the EXE project. Where you both added a reference to the DLL project assembly (like you should) and used #include on the header file. Like you should not. That's a guaranteed duplicate definition, #pragma once doesn't fix that.

不要使用头文件导出类型定义。始终使用程序集引用。

Don't use header files for exported type definitions. Always use assembly references.

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