问题描述
我似乎不知道如何将一个数组从导出的 C++ DLL 返回到我的 C# 程序.我从谷歌搜索中发现的唯一一件事是使用 Marshal.Copy() 将数组复制到缓冲区中,但这并没有给我想要返回的值,我不知道它给了我什么.
I can't seem to figure out how to return an array from an exported C++ DLL to my C# program. The only thing I've found from googling was using Marshal.Copy() to copy the array into a buffer but that doesn't give me the values I'm trying to return, I don't know what it's giving me.
这是我一直在尝试的:
导出函数:
extern "C" __declspec(dllexport) int* Test()
{
int arr[] = {1,2,3,4,5};
return arr;
}
C#部分:
[DllImport("Dump.dll")]
public extern static int[] test();
static void Main(string[] args)
{
Console.WriteLine(test()[0]);
Console.ReadKey();
}
我知道返回类型 int[] 可能是错误的,因为托管/非托管的差异,我只是不知道从哪里开始.除了将字符数组返回到字符串而不是整数数组之外,我似乎找不到任何答案.
I know the return type int[] is probably wrong because of the managed/unmanaged differences, I just have no idea where to go from here. I can't seem to find an answer for anything but returning character arrays to strings, not integer arrays.
我认为我使用 Marshal.Copy 获得的值不是我返回的值的原因是因为导出函数中的 'arr' 数组被删除了,但我不能 100% 确定,如果有人可以的话把这个弄清楚就好了.
I figured the reason the values I'm getting with Marshal.Copy are not the ones I'm returning is because the 'arr' array in the exported function gets deleted but I'm not 100% sure, if anyone can clear this up that would be great.
推荐答案
我已经实施了 Sriram 提出的解决方案.万一有人想要它在这里.
I have implemented the solution Sriram has proposed. In case someone wants it here it is.
在 C++ 中,您可以使用以下代码创建一个 DLL:
In C++ you create a DLL with this code:
extern "C" __declspec(dllexport) int* test()
{
int len = 5;
int * arr=new int[len+1];
arr[0]=len;
arr[1]=1;
arr[2]=2;
arr[3]=3;
arr[4]=4;
arr[5]=5;
return arr;
}
extern "C" __declspec(dllexport) int ReleaseMemory(int* pArray)
{
delete[] pArray;
return 0;
}
DLL 将被称为 InteropTestApp
.
然后你在 C# 中创建一个控制台应用程序.
Then you create a console application in C#.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
namespace DLLCall
{
class Program
{
[DllImport("C:\Devs\C++\Projects\Interop\InteropTestApp\Debug\InteropTestApp.dll")]
public static extern IntPtr test();
[DllImport("C:\Devs\C++\Projects\Interop\InteropTestApp\Debug\InteropTestApp.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int ReleaseMemory(IntPtr ptr);
static void Main(string[] args)
{
IntPtr ptr = test();
int arrayLength = Marshal.ReadInt32(ptr);
// points to arr[1], which is first value
IntPtr start = IntPtr.Add(ptr, 4);
int[] result = new int[arrayLength];
Marshal.Copy(start, result, 0, arrayLength);
ReleaseMemory(ptr);
Console.ReadKey();
}
}
}
result
现在包含值 1,2,3,4,5
.
希望对您有所帮助.
这篇关于将 C++ 数组返回到 C#的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!