从C＃字符串将char *传递给C DLL [英] pass char * to C DLL from C# string

问题描述

我需要在C＃应用程序的DLL中使用C函数库。我在使用char *参数调用DLL函数时遇到麻烦：

I need to use a library of C functions in a DLL from a C# application. I am having trouble calling DLL functions with char * arguments:

C DLL：

extern "C" __declspec(dllexport) int CopyFunc(char *, char *);
int CopyFunc(char *dest, char *src)
{
    strcpy(dest, src);
    return(strlen(src));
}

C＃应用程序需要看起来像这样：

the C# app needs to look something like this:

[DllImport("dork.dll")]
public static extern int CopyFunc(string dst, string src);

int GetFuncVal(string source, string dest)
{
    return(CopyFunc(dest,source));
}

我已经看到了使用string或StringBuilder或IntPtr替代示例的示例char *是DLL函数原型所需的，但我无法使它们中的任何一个正常工作。我得到的最常见的例外是PInvoke正在取消堆栈的平衡，因为函数调用与原型不匹配。

I've seen examples using string or StringBuilder, or IntPtr as replacements for the char * required by the DLL function prototype, but I've not been able to get any of them to work. The most common exception I get is that PInvoke is unbalancing the stack because the function call does not match the prototype.

有一个简单的解决方案吗？

Is there a simple solution to this?

推荐答案

更新外部函数的P / Invoke声明如下：

Update your P/Invoke declaration of your external function as such:

[DllImport("dork.dll")]
public static extern int CopyFunc([MarshalAs( UnmanagedType.LPStr )]string a, [MarshalAs( UnmanagedType.LPStr )] string b);

int GetFuncVal(string src, string dest)
{
    return(CopyFunc(dest,src));
}

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