标签：oid test private lex struct global using logs eve
1、 直接调用C++类库中的公共方法
使用DllImport特性对方法进行调用，比如一个C++类库SampleCppWrapper.dll中的公共方法：
extern "C" __declspec(dllexport) int __stdcall Add(int n1, int n2);
__stdcall表示调用约定：参数都是从右向左通过堆栈传递， 函数调用在返回前要由被调用者清理堆栈。
在C#中，调用如下：
[DllImport("SampleCppWrapper.dll")] private static extern int Add(int n1, int n2);
注意参数的类型，之后，可直接在C#编程中使用这个方法。
2、 调用C++类库中的类的方法
C#不能直接调用C++类库中的类，需要一种变通的解决方式，通过再做一个C++类库把要调用的类成员方法暴露出来，比如下面这个C++类：
SampleCppClass.h
#pragma once class __declspec(dllexport) SampleCppClass { public: SampleCppClass(void); ~SampleCppClass(void); int Add(int n1, int n2); int Sub(int n1, int n2); };
SampleCppClass.cpp
#include "SampleCppClass.h" SampleCppClass::SampleCppClass(void) { } SampleCppClass::~SampleCppClass(void) { } int SampleCppClass::Add(int n1, int n2) { return n1 + n2; } int SampleCppClass::Sub(int n1, int n2) { return n1 - n2; }
我们要调用SampleCppClass中的Add和Sub两个方法，所以我们再写一个C++类库，通过公共方法间接调用类成员方法：
SampleCppWrapper.h
#pragma once #include "..\SampleCppClass\SampleCppClass.h" namespace SampleCppWrapper { extern "C" __declspec(dllexport) int __stdcall Add(int n1, int n2); extern "C" __declspec(dllexport) int __stdcall Sub(int n1, int n2); }
SampleCppWrapper.cpp
#include "SampleCppWrapper.h" namespace SampleCppWrapper { SampleCppClass* g_pObj = new SampleCppClass(); int __stdcall Add(int n1, int n2) { return g_pObj->Add(n1, n2); } int __stdcall Sub(int n1, int n2) { return g_pObj->Sub(n1, n2); } }
在C#中，再调用SampleCppWrapper.dll中的公共方法：
[DllImport("SampleCppWrapper.dll")] private static extern int Add(int n1, int n2); [DllImport("SampleCppWrapper.dll")] private static extern int Sub(int n1, int n2);
3、 使用C++类库中的回调函数
C++的回调函数是一种事件响应机制，和C#的委托相似，比如一个C++类中的回调函数：
SampleCppClass.h
#pragma once typedef void (*LoopCallback)(void* pContext); class __declspec(dllexport) SampleCppClass { public: SampleCppClass(void); ~SampleCppClass(void); void SetCallbackFunc(LoopCallback callback); void SetCallbackContext(void* pContext); void Loop(); private: LoopCallback m_callback; void* m_pContext; };
SampleCppClass.cpp
#include "SampleCppClass.h" SampleCppClass::SampleCppClass(void) { } SampleCppClass::~SampleCppClass(void) { } void SampleCppClass::SetCallbackFunc(LoopCallback callback) { m_callback = callback; } void SampleCppClass::SetCallbackContext(void* pContext) { m_pContext = pContext; } void SampleCppClass::Loop() { for (int i=0; i<10; i++) { if (m_callback != NULL) { m_callback(m_pContext); } } }
我们通过C++再写一个类库进行封装，把类中的方法暴露出来：
SampleCppWrapper.h
#pragma once #include "..\SampleCppClass\SampleCppClass.h" namespace SampleCppWrapper { typedef void (__stdcall *LoopCallbackWrapper)(void* pContext); extern "C" __declspec(dllexport) void __stdcall SetCallbackFunc(LoopCallbackWrapper callback); extern "C" __declspec(dllexport) void __stdcall SetCallbackContext(void* pContext); extern "C" __declspec(dllexport) void __stdcall Loop(); }
SampleCppWrapper.cpp
#include "SampleCppWrapper.h" namespace SampleCppWrapper { LoopCallbackWrapper g_callbackWrapper; SampleCppClass* g_pObj = new SampleCppClass(); void LoopCallbackFunc(void* pContext); void __stdcall SetCallbackFunc(LoopCallbackWrapper callback) { g_callbackWrapper = callback; g_pObj->SetCallbackFunc(LoopCallbackFunc); } void __stdcall SetCallbackContext(void* pContext) { g_pObj->SetCallbackContext(pContext); } void __stdcall Loop() { g_pObj->Loop(); } void LoopCallbackFunc(void* pContext) { if (g_callbackWrapper != NULL) { g_callbackWrapper(pContext); } } }
然后，在C#中进行调用：
using System; using System.Runtime.InteropServices; using System.Windows.Forms; namespace SampleCsTest { public partial class Form1 : Form { [StructLayout(LayoutKind.Sequential)] private class Context { public Form1 Form { get; set; } } private delegate void LoopCallbackHandler(IntPtr pContext); private static LoopCallbackHandler callback = LoopCallback; [DllImport("SampleCppWrapper.dll")] private static extern void SetCallbackFunc(LoopCallbackHandler callback); [DllImport("SampleCppWrapper.dll")] private static extern void SetCallbackContext(IntPtr pContext); [DllImport("SampleCppWrapper.dll")] private static extern void Loop(); private Context ctx = new Context(); public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { SetCallbackFunc(callback); ctx.Form = this; IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(ctx)); Marshal.StructureToPtr(ctx, ptr, false); SetCallbackContext(ptr); } private void button1_Click(object sender, EventArgs e) { Loop(); } private static void LoopCallback(IntPtr pContext) { Context ctx = (Context)Marshal.PtrToStructure(pContext, typeof(Context)); ctx.Form.textBox1.Text += "callback" + Environment.NewLine; } } }
标签：oid test private lex struct global using logs eve
原文地址：http://www.cnblogs.com/lgyup/p/7116162.html
