C# api 动态加载Ｃ＋＋的ＤＬＬ函数方法

Ｃ＋＋函数如下：

// testdll3.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"

BOOL APIENTRY DllMain( HANDLE hModule,
                       DWORD ul_reason_for_call,
                       LPVOID lpReserved
      )
{
    return TRUE;
}

extern "C" __declspec(dllexport) int add(int * a,int * b)
{
return *a + *b;
}

Ｃ＃中动态加载方法：

首先写一个加载ＤＬＬ文件的类：

 

#region Win API 声明 class LoadDllAPI { [DllImport("kernel32.dll")] public extern static IntPtr LoadLibrary(string path); [DllImport("kernel32.dll")] public extern static IntPtr GetProcAddress(IntPtr lib, string funcName); [DllImport("kernel32.dll")] public extern static bool FreeLibrary(IntPtr lib); [DllImport("kernel32.dll")] public static extern IntPtr GetStdHandle(int nStdHandle); [DllImport("user32", EntryPoint = "CallWindowProc")] public static extern int CallWindowProc(IntPtr lpPrevWndFunc, int hwnd, int MSG, int wParam, int lParam); } #endregion public class LoadDll { IntPtr DllLib;//DLL文件名柄 #region 构造函数 public LoadDll() { } public LoadDll(string dllpath) { DllLib = LoadDllAPI.LoadLibrary(dllpath); } #endregion /// <summary> /// 析构函数 /// </summary> ~LoadDll() { LoadDllAPI.FreeLibrary(DllLib);//释放名柄 } public void initPath(string dllpath) { if (DllLib == IntPtr.Zero) { DllLib = LoadDllAPI.LoadLibrary(dllpath); } } /// <summary> /// 获取ＤＬＬ中一个方法的委托 /// </summary> /// <param name="methodname"></param> /// <param name="methodtype"></param> /// <returns></returns> public Delegate InvokeMethod(string methodname, Type methodtype) { IntPtr MethodPtr = LoadDllAPI.GetProcAddress(DllLib, methodname); return (Delegate)Marshal.GetDelegateForFunctionPointer(MethodPtr, methodtype); } }

 

以上方法编译．

调用：

 

* loadDLL.LoadDll loaddll = new loadDLL.LoadDll();／／实例化加载ＤＬＬ文件的类，，如上 * public delegate int delegateadd(IntPtr a,IntPtr b);／／声明此方法的一个委托 ／／一个调用用的按钮 private void button1_Click(object sender, EventArgs e) { loaddll.initPath("testdll3.dll");／／载入文件 delegateadd m = (delegateadd)loaddll.InvokeMethod("add", typeof(add));／／获取其中方法的委托 int a=1;int b=2; int re = m(out a, out b);//得到ＲＥ＝3，，成功 }