1、函数委托 类似于 C++中函数指针(∵我不知道这两货是否真的完全一样，∴用的是"类似于")

2、声明函数委托 方法类似于 声明函数指针

3、我的代码：

　　3.1、VC的DLL代码：

// *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***// 普通导出函数extern "C" __declspec(dllexport) int __stdcall TestZZ(int i, int j, int k, int m, int n){    return (i+j+k+m+n);}// *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***// exe中传入回调函数指针，并且调用typedef int (__stdcall * Callback_Test01)(int, int, int, int, int);extern "C" __declspec(dllexport) void __stdcall TestCB(Callback_Test01 _callback){    if (_callback)    {        int i = _callback(1,2,3,4,5);    }}

　　　　3.1.1、def文件内容：

LIBRARY DLL_ZEXPORTS    TestZZ    TestCB

　　3.2、C#代码：

private void button1_Click(object sender, EventArgs e)        {            AAA(1, 2, 3); // 用汇编查看 调用普通C#函数时的调用规则            int kk = TestZZ(1, 2, 3, 4 ,5); // 查看调用DLL导出函数时的调用规则            Fhh = 0;            TestCB(callback);   // ZC: 将函数委托传递给 VC的DLL 并在DLL中调用 -- (1)            MessageBox.Show(Fhh.ToString());            Fhh = 0;            callback02 = new Callback_Test01(TT01);            TestCB(callback02); // ZC: 将函数委托传递给 VC的DLL 并在DLL中调用 -- (2)            MessageBox.Show(Fhh.ToString());        }        int AAA(int i, int j, int k)        {            return (i + j + k);        }        //[DllImport("DLL_Z.dll", EntryPoint="TestZZ", CharSet=CharSet.Auto, CallingConvention=CallingConvention.StdCall)]        [DllImport("DLL_Z.dll", EntryPoint = "TestZZ", CharSet = CharSet.Auto)]        public static extern int TestZZ(Int32 i, Int32 j, Int32 k, Int32 m, Int32 n);        [DllImport("DLL_Z.dll", EntryPoint = "TestCB", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]        public static extern void TestCB([MarshalAs(UnmanagedType.FunctionPtr)] Callback_Test01 _callback);        // (委托)回调函数指针        [UnmanagedFunctionPointer(CallingConvention.StdCall)]        public delegate int Callback_Test01(int _i, int _j, int _k, int _m, int _n);        public static int Fhh = 0;        // 委托(回调函数) -- 方式(1)        // 需要访问类成员变量的回调函数实例        Callback_Test01 callback =            (i, j, k, m, n) =>            {                Fhh = (i + j + k + m + n); // 这里可以直接访问 类成员变量                //return (i + j + k + m + n);                return Fhh;            };        Callback_Test01 callback02 = null;//new Callback_Test01(TT01);        // 委托(回调函数) -- 方式(2)        int TT01(int i, int j, int k, int m, int n)        {            Fhh = (i + j + k + m + n); // 这里可以直接访问 类成员变量            //return (i + j + k + m + n);            return Fhh;        }

　　ZC: 测试感受：

　　ZC:　(1)、C#调用DLL中的函数，貌似默认的调用约定是 stdcall

　　ZC:　(2)、delegate 貌似它的默认调用约定也是stdcall

 

 

 

 

 

 

 

4、这里 测试的是 VC的DLL返回接口 让C#使用

　　4.1、C#代码：

　　　　4.1.1、接口声明

namespace WindowsFormsApplication_AAA{    [Guid("FCE9DCF3-9E38-441C-B10F-2BA31B57DCDC")]    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]    public interface IntfTest    {        unsafe Int32 TestZ01(int _i, int _j, int _k, int* _piOut);        unsafe Int32 TestZ02(int _i, int _j, int _k, int _m, int* _piOut);        unsafe Int32 TestZ03(int _i, int _j, int _k, int _m, int _n, int* _piOut);    }}

　　　　4.1.2、

[DllImport("DLL_Z.dll", EntryPoint = "IntfTest_Get", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]        public static extern int IntfTest_Get(ref IntfTest _intfTest);        private void button2_Click(object sender, EventArgs e)        {            callback02 = new Callback_Test01(TT01);            // 操作/使用 DLL返回的接口            IntfTest intfTest = null;            int iRtn = IntfTest_Get(ref intfTest);            unsafe            {                int iOut = 0;                intfTest.TestZ01(1, 2, 3, &iOut);            }        }

　　4.2、VC的DLL中的代码：

　　　　4.2.1、

// *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***// 导出 interface，供 exe使用IntfTest *g_pIntfTest;extern "C" __declspec(dllexport) int IntfTest_Get(IntfTest **_ppIntfTest){    (*_ppIntfTest) = NULL;    if ( NULL != g_pIntfTest )    {        // 当"IntfTest*"为局部变量时，C#会自动销毁接口，使得引用计数-1，∴这里需要+1        // 而 首次获取"IntfTest*"时，由于类构造函数中有增加引用计数的操作，∴不需要+1        g_pIntfTest->AddRef();        (*_ppIntfTest) = g_pIntfTest;        return 0;    }// ***    IntfTest *pObj = new TintfTest();    IUnknown *pIUnknown = NULL;    HRESULT hr = pObj->QueryInterface(IID_IUnknown, (void**)&pIUnknown);    pObj->Release();    pObj = NULL;    if (FAILED(hr))    {        return -1;    }    else    {        hr = pIUnknown->QueryInterface(IID_IntfTest, (void**)&g_pIntfTest);        pIUnknown->Release();        pIUnknown = NULL;        if (SUCCEEDED(hr))        {            (*_ppIntfTest) = g_pIntfTest;        }        else        {            return -2;        }    }    return 0;}

　　　　4.2.2、接口信息：

#ifndef __zzz_20160414__#define __zzz_20160414__#include 
     
      // // {FCE9DCF3-9E38-441C-B10F-2BA31B57DCDC}static const IID IID_IntfTest ={ 0xfce9dcf3, 0x9e38, 0x441c, { 0xb1, 0xf, 0x2b, 0xa3, 0x1b, 0x57, 0xdc, 0xdc } };interface IntfTest : public IUnknown{    virtual HRESULT __stdcall TestZ01(int _i, int _j, int _k, int* _piOut) = 0;    virtual HRESULT __stdcall TestZ02(int _i, int _j, int _k, int _m, int* _piOut) = 0;    virtual HRESULT __stdcall TestZ03(int _i, int _j, int _k, int _m, int _n, int* _piOut) = 0;};class TintfTest :public IntfTest{public:    TintfTest();public:    virtual HRESULT __stdcall TestZ01(int _i, int _j, int _k, int* _piOut);    virtual HRESULT __stdcall TestZ02(int _i, int _j, int _k, int _m, int* _piOut);    virtual HRESULT __stdcall TestZ03(int _i, int _j, int _k, int _m, int _n, int* _piOut);private:    long FlCount;public:    virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void **ppv)    {        if (iid == IID_IUnknown)        {            *ppv = static_cast
      
       (this);        }        else if (iid == IID_IntfTest)        {            *ppv = static_cast
       
        (this);        }        else        {            *ppv = NULL;            return E_NOINTERFACE;        }        AddRef();        return S_OK;    }    virtual ULONG STDMETHODCALLTYPE AddRef()    {        return ++FlCount;        //return InterlockedIncrement(&FlCount);    }    virtual ULONG STDMETHODCALLTYPE Release()    {        if (--FlCount == 0)        {            delete this;            return 0;        }        return FlCount;        //if (InterlockedDecrement(&FlCount) == 0)        //{        //    delete this;        //    return 0;        //}        //return FlCount;    }};TintfTest::TintfTest():    FlCount(0){    this->AddRef();}HRESULT __stdcall TintfTest::TestZ01(int _i, int _j, int _k, int* _piOut){    *_piOut = (_i + _j + _k);    return S_OK;}HRESULT __stdcall TintfTest::TestZ02(int _i, int _j, int _k, int _m, int* _piOut){    return S_OK;}HRESULT __stdcall TintfTest::TestZ03(int _i, int _j, int _k, int _m, int _n, int* _piOut){    return S_OK;}#endif // __zzz_20160414__
       
      
     

 

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