如何从C＃调用C ++函数 [英] How can I call to a C++ function from C#

问题描述

我有C ++代码。该代码包含Windows移动GPS启用/禁用功能。我想从C＃代码中调用该方法，这意味着当用户单击按钮时，C＃代码应调用C ++代码。

I have C++ code. That code contains Windows mobile GPS enable/disable functionality. I want to call that method from C# code, that means when the user clicks on a button, C# code should call into C++ code.

这是用于启用的C ++代码GPS功能：

This is the C++ code for enabling the GPS functionality:

#include "cppdll.h"

void Adder::add()
{
// TODO: Add your control notification handler code here
  HANDLE hDrv = CreateFile(TEXT("FNC1:"), GENERIC_READ | GENERIC_WRITE,
                0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
  if (0 == DeviceIoControl(hDrv, IOCTL_WID_GPS_ON, NULL, 0, NULL, 0, NULL, NULL))
  {
     RETAILMSG(1, (L"IOCTL_WID_RFID_ON Failed !! \r\n")); return;
  }
     CloseHandle(hDrv);

 return (x+y);
}

这是头文件 cppdll.h ：

class __declspec(dllexport) Adder
{
  public:
   Adder(){;};
  ~Adder(){;};
 void add();
};

如何使用C＃调用该函数？

How can I call that function using C#?

请，有人可以帮我解决这个问题吗？

Please, can anybody help me out with this issue?

推荐答案

我给你举个例子

您应像这样声明要导出的C ++函数（假设使用最新的MSVC编译器）：

You should declare your C++ functions for export like so (assuming recent MSVC compiler):

extern "C"             //No name mangling
__declspec(dllexport)  //Tells the compiler to export the function
int                    //Function return type     
__cdecl                //Specifies calling convention, cdelc is default, 
                       //so this can be omitted 
test(int number){
    return number + 1;
}

并将C ++项目编译为dll库。将项目目标扩展名设置为.dll，并将配置类型设置为动态库（.dll）。

And compile your C++ project as a dll library. Set your project target extension to .dll, and Configuration Type to Dynamic Library (.dll).

然后在C＃中声明：

public static class NativeTest
{
    private const string DllFilePath = @"c:\pathto\mydllfile.dll";

    [DllImport(DllFilePath , CallingConvention = CallingConvention.Cdecl)]
    private extern static int test(int number);

    public static int Test(int number)
    {
        return test(number);
    }
}

然后，您可以调用C ++测试函数会期望的。请注意，一旦您要传递字符串，数组，指针等，它可能会变得有些棘手。例如，请参见这个 SO问题。

Then you can call your C++ test function, as you would expect. Note that it may get a little tricky once you want to pass strings, arrays, pointers, etc. See for example this SO question.

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