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VS创建C++动态库和C#访问过程

news 2025/10/21 15:23:06

以C++ 14版本和net 8.0为例，使用vs2022工具

1 新建项目

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2 添加类文件

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3 项目文件列表如下

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4 写头文件

#pragma once#ifdef TIMECONVERTER_EXPORTS
#define TIMECONVERTER_API __declspec(dllexport)
#else
#define TIMECONVERTER_API __declspec(dllimport)
#endifextern "C" 
{// 将时间转换为字符串TIMECONVERTER_API const char* ConvertTimeToString(int year, int month, int day,int hour, int minute, int second);TIMECONVERTER_API const char* GetCurrentTimeString();// 释放字符串内存TIMECONVERTER_API void FreeString(char* str);
}

5 写cpp文件

#include "pch.h"#include "TimeConverter.h"
#include <string>
#include <sstream>
#include <iomanip>
#include <iostream>using namespace std;// 导出的函数：将时间转换为字符串
extern "C" TIMECONVERTER_API const char* ConvertTimeToString(int year, int month, int day,int hour, int minute, int second)
{try {// 验证输入参数if (year < 1900 || year > 2100) return nullptr;if (month < 1 || month > 12) return nullptr;if (day < 1 || day > 31) return nullptr;if (hour < 0 || hour > 23) return nullptr;if (minute < 0 || minute > 59) return nullptr;if (second < 0 || second > 59) return nullptr;// 格式化时间字符串stringstream ss;ss << setw(4) << setfill('0') << year << "-"<< setw(2) << setfill('0') << month << "-"<< setw(2) << setfill('0') << day << " "<< setw(2) << setfill('0') << hour << ":"<< setw(2) << setfill('0') << minute << ":"<< setw(2) << setfill('0') << second;string result = ss.str();// 分配内存并返回字符串char* output = new char[result.length() + 1];strcpy_s(output, result.length() + 1, result.c_str());return output;}catch (...) {return nullptr;}
}// 导出的函数：释放字符串内存
extern "C" TIMECONVERTER_API void FreeString(char* str)
{if (str != nullptr){delete[] str;}
}extern "C" TIMECONVERTER_API const char* GetCurrentTimeString()
{try {time_t now = time(nullptr);tm timeInfo;localtime_s(&timeInfo, &now);return ConvertTimeToString(timeInfo.tm_year + 1900,timeInfo.tm_mon + 1,timeInfo.tm_mday,timeInfo.tm_hour,timeInfo.tm_min,timeInfo.tm_sec);}catch (...){return nullptr;}
}

6 注意配置信息

配置属性 → C/C++ → 预处理器 → 预处理器定义：添加 TIMECONVERTER_EXPORTS

配置属性 → 常规 → 配置类型：动态库(.dll)

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7 新建C#项目拷贝dll文件

拷贝C++的dll文件到C#项目生成文件目录下

8 引用dll测试

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.InteropServices;namespace StringTimeTest
{public partial class UserControl1: UserControl{public UserControl1(){InitializeComponent();}private void button1_Click(object sender, EventArgs e){Console.WriteLine("C++ 时间转换器测试");Console.WriteLine("==================");TestTimeConversion("当前时间");// 测试用例1：当前时间TestTimeConversion(2024, 1, 15, 14, 30, 45, "测试用例1 - 当前时间");// 测试用例2：午夜时间TestTimeConversion(2024, 12, 31, 0, 0, 0, "测试用例2 - 午夜时间");// 测试用例3：边界值测试TestTimeConversion(2024, 1, 1, 23, 59, 59, "测试用例3 - 边界值");// 测试用例4：无效时间（应该返回空）TestTimeConversion(2024, 13, 32, 25, 61, 61, "测试用例4 - 无效时间");// 测试用例5：使用DateTime.NowDateTime now = DateTime.Now;TestTimeConversion(now.Year, now.Month, now.Day,now.Hour, now.Minute, now.Second,"测试用例5 - 实时时间");Console.WriteLine("\n按任意键退出...");}// 导入C++ DLL函数[DllImport("TimeConverter.dll", CallingConvention = CallingConvention.Cdecl)]private static extern IntPtr ConvertTimeToString(int year, int month, int day,int hour, int minute, int second);[DllImport("TimeConverter.dll", CallingConvention = CallingConvention.Cdecl)]private static extern void FreeString(IntPtr str);[DllImport("TimeConverter.dll", CallingConvention = CallingConvention.Cdecl)]private static extern IntPtr GetCurrentTimeString();static void TestTimeConversion(int year, int month, int day,int hour, int minute, int second, string testName){Console.WriteLine($"\n{testName}:");Console.WriteLine($"输入: {year}-{month:D2}-{day:D2} {hour:D2}:{minute:D2}:{second:D2}");IntPtr resultPtr = ConvertTimeToString(year, month, day, hour, minute, second);if (resultPtr != IntPtr.Zero){string result = Marshal.PtrToStringAnsi(resultPtr);Console.WriteLine($"输出: {result}");// 释放C++分配的内存FreeString(resultPtr);}else{Console.WriteLine("输出: 无效的时间参数！");}}static void TestTimeConversion( string testName){Console.WriteLine($"\n{testName}:");IntPtr resultPtr = GetCurrentTimeString();if (resultPtr != IntPtr.Zero){string result = Marshal.PtrToStringAnsi(resultPtr);Console.WriteLine($"输出: {result}");// 释放C++分配的内存FreeString(resultPtr);}else{Console.WriteLine("输出: 无效的时间参数！");}}}
}