英文:
Can not parse a string from C++ to C#
问题
I write a C# dll and call it from C++ function. But when I parse a string from C++ to C# function, I will show something weird like this:
> d^¡Aè☺
Here is my C++ code:
#include "pch.h"#include<stdio.h>#include<Windows.h>#include<string>using namespace System;using namespace System::Runtime::InteropServices;using namespace System::Reflection;int main(){const char* pemodule = ("C:\\Users\\source\\repos\\ClassLibrary2\\ClassLibrary2\\bin\\Debug\\ClassLibrary2.dll");HMODULE hlib = LoadLibraryA(pemodule);typedef int(__cdecl *add)(int a, int b);typedef int(__cdecl* AntiMacro)(std::string path);auto pAntiMacro = (AntiMacro)GetProcAddress(hlib, "AntiMacro");std::string path = "C:\\macro\\test";int a = pAntiMacro(path);printf("%d\n", a);return 0;}
And here is my C# DLL:
[DllExport]public static int AntiMacro(string filepath){Console.WriteLine(filepath);bool isFolder = false;string fullpath = "";try{fullpath = Path.GetFullPath(filepath);Console.WriteLine(fullpath.ToString());}catch (Exception){Console.WriteLine(fullpath);Console.WriteLine("Invalid path 1");return 1;}
I tried to change
std::string path = "C:\\macro\\test"
to
const char *path = "C:\\macro\\test"
But it still not working, is that string in C++ is different from C#?
英文:
I write a C# dll and call it from C++ function. But when i parse a string from C++ to C# function, i will show something weird like this:
> d^¡Aè☺
Here is my C++ code:
#include "pch.h"#include<stdio.h>#include<Windows.h>#include<string>using namespace System;using namespace System::Runtime::InteropServices;using namespace System::Reflection;int main(){const char* pemodule = ("C:\\Users\\source\\repos\\ClassLibrary2\\ClassLibrary2\\bin\\Debug\\ClassLibrary2.dll");HMODULE hlib = LoadLibraryA(pemodule);typedef int(__cdecl *add)(int a, int b);typedef int(__cdecl* AntiMacro)(std::string path);auto pAntiMacro = (AntiMacro)GetProcAddress(hlib, "AntiMacro");std::string path = "C:\\macro\\test";int a = pAntiMacro(path);printf("%d\n", a);return 0;}
And here is my C# DLL:
[DllExport]public static int AntiMacro(string filepath){Console.WriteLine(filepath);bool isFolder = false;string fullpath = "";try{fullpath = Path.GetFullPath(filepath);Console.WriteLine(fullpath.ToString());}catch (Exception){Console.WriteLine(fullpath);Console.WriteLine("Invalid path 1");return 1;}
I tried to change
std::string path = "C:\\macro\\test"
to
const char *path = "C:\\macro\\test"
But it still not working, is that string in C++ is different from C#?
答案1
得分: 3
你首先需要将 std::string 转换为 char*
std::string path = "C:\\macro\\test";const char *cstr = path.data();int a = pAntiMacro(cstr);
你还需要为字符串进行编组
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPStr)]string filepath){
但使用 C++/CLI 可能是更好的选择。
英文:
You first need to convert std:string into char*
std::string path = "C:\\macro\\test";const char *cstr = path.data();int a = pAntiMacro(cstr);
You also need marshalling for the string
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPStr)]string filepath){
But using C++/CLI might be a better option either way.
答案2
得分: 2
To work with C# DLLs in C++, you need to use the .NET Framework's Common Language Runtime (CLR) and interact with the DLL through managed interop: https://learn.microsoft.com/en-us/cpp/dotnet/overview-of-marshaling-in-cpp?view=msvc-170
Also see this: https://stackoverflow.com/questions/3539334/how-to-turn-systemstring-into-stdstring https://stackoverflow.com/a/53016935/5033623
I highly do not recommend this approach though unless you have a very specific reason to work with C# API calls in your native application. It's usually the other way around.
英文:
To work with C# DLLs in C++, you need to use the .NET Framework's Common Language Runtime (CLR) and interact with the DLL through managed interop:
https://learn.microsoft.com/en-us/cpp/dotnet/overview-of-marshaling-in-cpp?view=msvc-170
Also see this:
https://stackoverflow.com/questions/3539334/how-to-turn-systemstring-into-stdstring
https://stackoverflow.com/a/53016935/5033623
I highly do not recommend this approach though unless you have a very specific reason to work with C# API calls in your native application. It's usually the other way around.
答案3
得分: 0
UPDATE: 我找到了解决方案。正如Charlieface所说：我需要将这段代码放入我的代码中：
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPStr)]string filepath){
但仍然无法正常工作，所以我稍微修改了它：
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPUTF8Str)]string filepath)
我将UnmanagedType.LPStr更改为UnmanagedType.LPUTF8Str，它完美运行。并根据Charlieface提供的建议编辑了我的C++代码。
英文:
UPDATE: i found the solution. As Charlieface said: i need to put this in my code:
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPStr)]string filepath){
But it still not working, so i rewrite it a little bit:
[DllExport]public static int AntiMacro([MarshalAs(UnmanagedType.LPUTF8Str)]string filepath)
I change UnmanagedType.LPStr to UnmanagedType.LPUTF8Str and it work perfectly. And edit my C++ code as Charlieface provided.
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