本文通过实例代码说明如何在托管的C#代码中调用非托管的Win32 API或者自己用C/C++写的Dll中的函数，以及如何传递输入、输出字符串参数，结构类型参数等问题。 Win32 C/C++ DLL代码如下(最终编译成dll.dll)： #include "stdafx.h" #include <stdio.h> #ifdef _MANAGED #pragma managed(push, off) #endif //简单的函数调用测试 extern "C" __declspec(dllexport) int Test(void) { return 34; } //输入输出字符串传递测试 extern "C" __declspec(dllexport) int TCharPara(char *in, int len, char *out) { memcpy(out, in, len); return 0; } //结构参数传递测试 struct _XY { int x; int y; }; extern "C" __declspec(dllexport) int TStructPara(struct _XY *xy) { xy->x = 5; xy->y = 5; return 0; } //回调函数测试 typedef void (CALLBACK *CBFunc)(char *); extern "C" __declspec(dllexport) int TCallback(CBFunc pf, char *out) { (*pf)(out); return 0; } #ifdef _MANAGED #pragma managed(pop) #endif 调用Win32 C/C++ dll中函数的托管C#代码如下： using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Runtime.InteropServices; namespace TCallCDll { //用于测试结构参数传递，对应Win32 dll中的结构_XY [StructLayout(LayoutKind.Sequential)] public struct _XY { public int x; public int y; }; //Win32 C/C++ dll中的函数TCallback回调此函数 public delegate void OurDllCallBack(String iin); //user32.dll中的EnumWindows函数回调此函数 public delegate bool SysCallBack(int hwnd, int lParam); public class TCallCDll{ [DllImport("dll.dll")] // //iin: 输入参数 //oout: 输出参数 // public static extern int TCharPara(String iin, int len, StringBuilder oout); //测试结构参数传递的函数 [DllImport("dll.dll")] public static extern int TStructPara(ref _XY xy); //自己的dll函数回调测试 [DllImport("dll.dll", CharSet = CharSet.Ansi)] public static extern void TCallback(OurDllCallBack f, String s); //user32.dll中的函数回调测试 [DllImport("user32.dll")] public static extern int EnumWindows(SysCallBack x, int y); } public partial class callCDllMain : Form { public callCDllMain() { InitializeComponent(); } //提供给dll.dll中的TCallback回调的函数 public static void ff(String s) { Console.WriteLine(s); } //提供给user32.dll中的EnumWindows回调的函数 public static bool Report(int hwnd, int lParam) { Console.Write("Window handle is "); Console.WriteLine(hwnd); return true; } private void Form1_Load(object sender, EventArgs e) { StringBuilder a = new StringBuilder(3); TCallCDll.TCharPara("ABC", 3, a); this.Text = a.ToString(); _XY xy = new _XY(); TCallCDll.TStructPara(ref xy); this.Text += "x:" + xy.x + ", y:" + xy.y; OurDllCallBack fff = new OurDllCallBack(ff); TCallCDll.TCallback(fff, "This string is output in C&C++ dll call back function set in C# code/n"); SysCallBack cb = new SysCallBack(Report); TCallCDll.EnumWindows(cb, 0); } } } 本文来自博客，转载请标明出处：http://blog.csdn.net/ZOLoveGD/archive/2009/04/03/4046845.aspx
