检测Windows电脑网络是否在线、离线方法（c++）--＞ConnectivityChanged

1 方法：调用Windows的com接口，

        CLSID_NetworkListManager

        IID_INetworkListManager

        IID_IConnectionPointContainer

        IID_INetworkListManagerEvents

2 代码：如下：

// testNetStatus.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//
 
#include 
#include 
#include 
#pragma comment(lib, "ole32.lib")
 
class MyNetWorkEvent : public INetworkListManagerEvents
{
public:
  MyNetWorkEvent() {
    m_ref = 1;
  }
  /*
  typedef enum NLM_CONNECTIVITY {
    NLM_CONNECTIVITY_DISCONNECTED       = 0x0000, // 断开连接
    NLM_CONNECTIVITY_IPV4_NOTRAFFIC     = 0x0001, // 不通
    NLM_CONNECTIVITY_IPV6_NOTRAFFIC     = 0x0002,
    NLM_CONNECTIVITY_IPV4_SUBNET        = 0x0010,
    NLM_CONNECTIVITY_IPV4_LOCALNETWORK  = 0x0020,
    NLM_CONNECTIVITY_IPV4_INTERNET      = 0x0040, // 有网
    NLM_CONNECTIVITY_IPV6_SUBNET        = 0x0100,
    NLM_CONNECTIVITY_IPV6_LOCALNETWORK  = 0x0200,
    NLM_CONNECTIVITY_IPV6_INTERNET      = 0x0400
  } NLM_CONNECTIVITY;
  ConnectivityChanged: 0003 // 局域网，没网
  ConnectivityChanged: 0000 // 断开连接
  ConnectivityChanged: 0042 // 局域网，能上网
  */
  virtual HRESULT STDMETHODCALLTYPE ConnectivityChanged(NLM_CONNECTIVITY newConnectivity)
  {
 
    printf("ConnectivityChanged: %04X\n", newConnectivity);
    return S_OK;
  }
  virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppvObject)
  {
    HRESULT Result = S_OK;
    if (IsEqualIID(riid, IID_IUnknown))
    {
      *ppvObject = (IUnknown *)this;
    }
    else if (IsEqualIID(riid, IID_INetworkListManagerEvents))
    {
      *ppvObject = (INetworkListManagerEvents *)this;
    }
    else
    {
      Result = E_NOINTERFACE;
    }
 
    return Result;
  }
  virtual ULONG STDMETHODCALLTYPE AddRef(void)
  {
    return (ULONG)InterlockedIncrement(&m_ref);
  }
 
 
  virtual ULONG STDMETHODCALLTYPE Release(void)
  {
    LONG Result = InterlockedDecrement(&m_ref);
    if (Result == 0)
      delete this;
    return (ULONG)Result;
  }
private:
  LONG m_ref;
};
 
int main()
{
  CoInitialize(NULL);
 
  INetworkListManager *pNetworkListManager = NULL;
  HRESULT hr = CoCreateInstance(CLSID_NetworkListManager, NULL, CLSCTX_ALL, IID_INetworkListManager, (LPVOID *)&pNetworkListManager);
  printf("CLSID_NetworkListManager: %d\n", FAILED(hr));
 
  VARIANT_BOOL bConnected = VARIANT_FALSE;
  hr = pNetworkListManager->get_IsConnected(&bConnected);
  printf("is Connected: %d %d\n", bConnected, FAILED(hr));
 
  IConnectionPointContainer *pCPContainer = NULL;
  hr = pNetworkListManager->QueryInterface(IID_IConnectionPointContainer, (void**)&pCPContainer);
  IConnectionPoint *pConnectPoint = NULL;
  hr = pCPContainer->FindConnectionPoint(IID_INetworkListManagerEvents, &pConnectPoint);
 
  DWORD Cookie = 0;
  MyNetWorkEvent* pMyEvent = new MyNetWorkEvent();
  pConnectPoint->Advise((IUnknown*)pMyEvent, &Cookie);
 
  MSG msg;
  while (GetMessage(&msg, NULL, 0, 0))
  {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
    if (msg.message == WM_QUIT)
    {
      break;
    }
  }
  pConnectPoint->Unadvise(Cookie);
  pConnectPoint->Release();
 
  pCPContainer->Release();
  pNetworkListManager->Release();
 
  system("pause");
  CoUninitialize();
  return 0;
}

3 测试结果截图：能检测到网络状态变化的消息：

• 断开电脑网络 : 0x0000
• 然后重新连接 : 0x0003->0x0004