编写依赖自有C#库的Assimp C++包装器遇编译及引用问题求助

Let's break down your issues step by step—first fixing the C++/CLI compilation errors, then resolving the C# namespace not found problem.

Most of your errors stem from missing references to your C# Graphics::OpenGL library, C++/CLI syntax quirks, and incorrect header structure. Here's how to fix each one:

1. Add Reference to Your C# Graphics.OpenGL Library #

The core error ('Graphics': is not a class or namespace name) happens because your C++/CLI project doesn't know about your C# library. To fix this:

• Right-click your C++/CLI project in Visual Studio → Add → Reference → Select your Graphics.OpenGL C# library.
• Add a #using directive at the top of your header to import the assembly (adjust the path if the DLL isn't in the same output folder):

  #using "Graphics.OpenGL.dll"
  

• Build your Graphics.OpenGL project first so the DLL exists when compiling the wrapper.

2. Fix Generic Type & Managed Reference Syntax #

Errors like C2955 'System::Collections::Generic::List': use of class generic requires generic argument list and E2227 are a mix of missing assembly references and incorrect C++/CLI syntax:

• Add using namespace Graphics::OpenGL; to your header to avoid typing the full namespace every time, which reduces syntax errors.
• For managed generic classes from C# (like VertexArray<T>), you need to use the hat (^) to declare them as managed references, not value types. For example:

  // Wrong: No ^ for managed generic
  Graphics::OpenGL::VertexArray<float> VAO;
  // Correct: Use ^ for managed reference
  VertexArray<float>^ VAO;
  

3. Fix the Draw Method Parameter Name Conflict #

The C2182 'Draw': illegal use of type 'void' error comes from naming your parameter Shader—which matches the type name Graphics::OpenGL::Shader. Rename the parameter to something distinct:

// Wrong: Parameter name matches type name
void Draw(Graphics::OpenGL::Shader^ Shader);
// Correct: Renamed parameter
void Draw(Shader^ shader);

4. Fix Header Guard Placement #

Your header guard is inside the Assimp namespace, which is incorrect. Wrap the entire file content to prevent multiple inclusions:

#pragma once
#ifndef MESH_H
#define MESH_H

// Your #using and using directives go here

namespace Assimp {
// Your Mesh class code goes here
} // namespace Assimp

#endif // MESH_H

Once your C++/CLI project compiles, resolve the C# reference issue with these steps:

• Ensure your C++/CLI project is built to generate its DLL (e.g., AssimpWrapper.dll).
• In your C# project, right-click References → Add Reference → Browse to the C++/CLI project's output directory and select the DLL.
• Match the .NET version between your C++/CLI and C# projects (critical for .NET Core/.NET 5+).
• Add using Assimp; at the top of your C# file where you want to use the Mesh class.
• If the DLL isn't copied to your C# project's bin folder, adjust the C++/CLI project's output path to match your C# project's build directory.

Here's what your fixed header should look like:

#pragma once
#ifndef MESH_H
#define MESH_H

// Reference your C# OpenGL assembly
#using "Graphics.OpenGL.dll"

using namespace System;
using namespace System::Collections::Generic;
using namespace Graphics::OpenGL;

namespace Assimp {
public ref class Mesh {
public:
    List<Vertex>^ vertices;
    List<UInt32>^ indices;
    List<Texture>^ textures;
    VertexArray<float>^ VAO;

    Mesh(List<Vertex>^ Vertices, List<UInt32>^ Indices, List<Texture>^ Textures);
    void Draw(Shader^ shader);

private:
    void setupMesh();
};
} // namespace Assimp

#endif // MESH_H

内容的提问来源于stack exchange，提问作者O-BL