WPF与C++ 动态库交互

WPF与C++动态库交互技术详解

一、基本交互方式概述

WPF应用程序与C++动态库交互主要有以下几种方式：

1. ​​P/Invoke调用​​（平台调用）
2. ​​COM互操作​​
3. ​​C++/CLI桥接层​​
4. ​​内存映射文件​​
5. ​​命名管道/Socket通信​​

本文将重点介绍最常用的P/Invoke和C++/CLI两种方式。

二、P/Invoke调用C++动态库

1. C++动态库创建

​​示例C++代码 (MyLibrary.cpp):​​

#include <string>
#include <vector>extern "C" {// 简单函数__declspec(dllexport) int AddNumbers(int a, int b) {return a + b;}// 返回字符串__declspec(dllexport) const char* GetMessage() {return "Hello from C++";}// 结构体处理struct Point {double X;double Y;};__declspec(dllexport) Point GetPoint(double x, double y) {Point p = {x, y};return p;}
}

​​编译为DLL:​​

cl /EHsc /LD MyLibrary.cpp /link /OUT:MyLibrary.dll

2. WPF中调用C++ DLL

​​P/Invoke声明 (NativeMethods.cs):​​

using System;
using System.Runtime.InteropServices;public static class NativeMethods
{// 简单函数调用[DllImport("MyLibrary.dll", CallingConvention = CallingConvention.Cdecl)]public static extern int AddNumbers(int a, int b);// 返回字符串[DllImport("MyLibrary.dll", CallingConvention = CallingConvention.Cdecl)]public static extern IntPtr GetMessage();// 结构体处理[StructLayout(LayoutKind.Sequential)]public struct Point{public double X;public double Y;}[DllImport("MyLibrary.dll", CallingConvention = CallingConvention.Cdecl)]public static extern Point GetPoint(double x, double y);// 辅助方法：释放字符串内存[DllImport("MyLibrary.dll", CallingConvention = CallingConvention.Cdecl)]public static extern void FreeString(IntPtr str);
}

​​注意​​：如果C++函数返回的是动态分配的字符串，需要在C++端提供释放函数。

​​改进的C++代码 (添加FreeString):​​

extern "C" {__declspec