如何将 C 数组映射到 C#？

发布于 2024-10-06 19:58:37 字数 1024 浏览 6 评论 0原文

我的问题与尝试从 C# 调用用 C 编写的函数有关。我查看了 C 库附带的头文件，以了解 C dll 中存在的函数。这是我看到的：

C 代码（对于名为“LocGetLocations”的函数）：

typedef enum {
    eLocNoError,
    eLocInvalidCriteria,
    eLocNoMatch, 
    eLocNoMoreLocations,
    eLocConnectionError, 
    eLocContextError,
    eLocMemoryError
} tLocGetStatus; 

typedef void *tLocFindCtx;

typedef void *tLocation;    

PREFIX unsigned int POSTFIX LocGetLocations
(
    tLocFindCtx pCtx, 
    tLocation *pLoc,
    unsigned int pNumLocations,
    tLocGetStatus *pStatus
);

在 C# 中，我有这样的：

[DllImport(@"VertexNative\Location.dll")]
public static extern uint LocGetLocations(IntPtr findContext, out byte[] locations, uint numberLocations, out int status);

问题是我不太知道如何处理 C# 中的 pLoc 参数。我将其作为字节数组传递，尽管我不确定这是否正确。 C 库的文档说该参数是指向句柄数组的指针。

如何在 C# 端获取数组并访问其数据？

我在 C 语言中给出的示例如下所示：

tLocation lLocation[20];

// other stuff

LocGetLocations(lCtx, lLocation, 20, &lStatus)

任何帮助将不胜感激！

原文

My question has to do with trying to call a function written in C from C#. I've looked in a header file that came with the C library to understand the functions as they exist in the C dll. Here's what I see:

C code (for a function called "LocGetLocations"):

typedef enum {
    eLocNoError,
    eLocInvalidCriteria,
    eLocNoMatch, 
    eLocNoMoreLocations,
    eLocConnectionError, 
    eLocContextError,
    eLocMemoryError
} tLocGetStatus; 

typedef void *tLocFindCtx;

typedef void *tLocation;    

PREFIX unsigned int POSTFIX LocGetLocations
(
    tLocFindCtx pCtx, 
    tLocation *pLoc,
    unsigned int pNumLocations,
    tLocGetStatus *pStatus
);

In C#, I have this:

[DllImport(@"VertexNative\Location.dll")]
public static extern uint LocGetLocations(IntPtr findContext, out byte[] locations, uint numberLocations, out int status);

The problem is that I don't quite know how to handle the pLoc parameter in C#. I'm bringing it over as a byte array, although I'm not sure if that is correct. The C library's documentation says that that parameter is a pointer to an array of handles.

How can I get an array back on the C# side and access its data?

The example I was given in C, looks like this:

tLocation lLocation[20];

// other stuff

LocGetLocations(lCtx, lLocation, 20, &lStatus)

Any help would be much appreciated!

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我爱人 2024-10-13 19:58:37

一般来说，唯一重要的是参数的大小。我记得枚举在 C 中是整数，所以你可以简单地使用它。或者更好的是，在 C# 中重新创建相同的枚举，我认为它会起作用。要记住的一件事是，在处理复杂结构时，需要使用属性来告诉框架所需的成员对齐方式。

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云醉月微眠 2024-10-13 19:58:37

最后，这个签名有效：

[DllImport(@"VertexNative\Location.dll")]
public static extern uint LocGetLocations(IntPtr findContext, [Out] IntPtr[] locations, uint numberLocations, out int status);

我可以这样称呼它（需要一些重构）：

IntPtr[] locations = new IntPtr[20];
int status;
// findContext is gotten from another method invocation
uint result = GeoCodesNative.LocGetLocations(findContext, locations, 20, out status);

感谢您的帮助！

In the end, this signature works:

[DllImport(@"VertexNative\Location.dll")]
public static extern uint LocGetLocations(IntPtr findContext, [Out] IntPtr[] locations, uint numberLocations, out int status);

And I can call it like this (some refactoring needed):

IntPtr[] locations = new IntPtr[20];
int status;
// findContext is gotten from another method invocation
uint result = GeoCodesNative.LocGetLocations(findContext, locations, 20, out status);

Thanks for the help!

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