c# COM组件原理详解

// SimpleMath.h
#pragma once
#include <Windows.h>
// {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}
DEFINE_GUID(IID_ISimpleMath, 
    0xXXXXXXXX, 0xXXXX, 0xXXXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX);
interface ISimpleMath : public IUnknown
{
public:
    virtual HRESULT __stdcall Add(int a, int b, int* result) = 0;
    virtual HRESULT __stdcall Multiply(int a, int b, int* result) = 0;
};

// SimpleMath.cpp
#include "SimpleMath.h"
class SimpleMath : public ISimpleMath
{
public:
    // Implement the Add method
    HRESULT __stdcall Add(int a, int b, int* result) override
    {
        *result = a + b;
        return S_OK;
    }
    // Implement the Multiply method
    HRESULT __stdcall Multiply(int a, int b, int* result) override
    {
        *result = a * b;
        return S_OK;
    }
    // Implement the IUnknown methods
    ULONG __stdcall AddRef() override { return 1; }
    ULONG __stdcall Release() override { return 1; }
    HRESULT __stdcall QueryInterface(const IID& iid, void** ppv) override
    {
        if (iid == IID_ISimpleMath || iid == IID_IUnknown)
        {
            *ppv = static_cast<ISimpleMath*>(this);
            AddRef();
            return S_OK;
        }
        *ppv = nullptr;
        return E_NOINTERFACE;
    }
};
// Export the CreateInstance function to create an instance of the COM component
extern "C" __declspec(dllexport) HRESULT CreateInstance(ISimpleMath** math)
{
    if (math == nullptr)
        return E_POINTER;
    *math = new SimpleMath();
    if (*math == nullptr)
        return E_OUTOFMEMORY;
    return S_OK;
}

#include <Windows.h>
#include "SimpleMath.h"
int main()
{
    CoInitialize(nullptr);
    ISimpleMath* math = nullptr;
    HRESULT hr = CoCreateInstance(CLSID_ISimpleMath, nullptr, CLSCTX_INPROC_SERVER, IID_ISimpleMath, reinterpret_cast<void**>(&math));
    if (SUCCEEDED(hr))
    {
        int resultAdd, resultMultiply;
        math->Add(5, 3, &resultAdd);
        math->Multiply(5, 3, &resultMultiply);
        printf("Addition result: %d\n", resultAdd);
        printf("Multiplication result: %d\n", resultMultiply);
        math->Release();
    }
    else
    {
        printf("Failed to create instance of SimpleMath. Error code: 0x%08X\n", hr);
    }
    CoUninitialize();
    return 0;
}