一段能够下载文件的源代码

  // 在工程中加入 Urlmon.lib

//---------------------------------------------------------------------------

#include <vcl.h>
#include <windows.h>
#include <Urlmon.h>
#pragma hdrstop
#include "Unit1.h"
//---------------------------------------------------------------------------
cImpMonikerCallback objImpCallback;
//---------------------------------------------------------------------------

#pragma argsused
WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
        LPUNKNOWN pCaller;
        pCaller = NULL;
        DWORD dwResv = 0;
        objImpCallback.lpfnCB = (IBindStatusCallback *)&objImpCallback;

        HRESULT hRet=URLDownloadToFile(pCaller,"http://127.0.0.1:30000/download/icon.zip","d:\temp\icon.zip",dwResv,objImpCallback.lpfnCB);

  if(hRet==S_OK)
    MessageBox(NULL,"成功下载文件","",MB_OK);

  return 0;
}
//---------------------------------------------------------------------------

cImpMonikerCallback::cImpMonikerCallback()
{
  m_cRef = 1;
  m_pbinding = NULL;
};
//---------------------------------------------------------------------------

cImpMonikerCallback::~cImpMonikerCallback()
{
  if(m_pbinding)
    m_pbinding->Release();
};
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::QueryInterface(REFIID riid,void ** ppv)
{
  *ppv = NULL;
  if (riid==IID_IUnknown ¦¦ riid==IID_IBindStatusCallback)
  {
    *ppv = this;
    AddRef();
    return S_OK;
  }
  return E_NOINTERFACE;
};
//---------------------------------------------------------------------------

STDMETHODIMP_(ULONG) cImpMonikerCallback::AddRef()
{
  return m_cRef++;
}
//---------------------------------------------------------------------------

STDMETHODIMP_(ULONG) cImpMonikerCallback::Release()
{
  if(--m_cRef==0)
  {
    delete this;
    return 0;
  }
  return m_cRef;
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::GetBindInfo(DWORD* pgrfBINDF, BINDINFO* pbindinfo)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnStartBinding(DWORD grfBSCOption, IBinding* pbinding)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::GetPriority(LONG* pnPriority)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnProgress(ULONG ulProgress, ULONG ulProgressMax,ULONG ulStatusCode, LPCWSTR szStatusText)
{
  return(NOERROR);
};
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnDataAvailable(DWORD grfBSCF, DWORD dwSize, FORMATETC *pfmtetc,STGMEDIUM* pstgmed)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnObjectAvailable(REFIID riid, IUnknown* punk)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnLowResource(DWORD dwReserved)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

STDMETHODIMP cImpMonikerCallback::OnStopBinding(HRESULT hrStatus, LPCWSTR szText)
{
  return(NOERROR);
}
//---------------------------------------------------------------------------

///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////

class cImpMonikerCallback:public IBindStatusCallback
{
  DWORD m_cRef;
  IBinding* m_pbinding;
public:
        cImpMonikerCallback();
        ~cImpMonikerCallback();

        STDMETHODIMP QueryInterface(REFIID riid,void ** ppv);
        STDMETHODIMP_(ULONG) AddRef();//    { return m_cRef++; }
  STDMETHODIMP_(ULONG) Release();
        STDMETHODIMP GetBindInfo(DWORD* pgrfBINDF, BINDINFO* pbindinfo);
        STDMETHODIMP OnStartBinding(DWORD grfBSCOption, IBinding* pbinding);
        STDMETHODIMP GetPriority(LONG* pnPriority);
        STDMETHODIMP OnProgress(ULONG ulProgress, ULONG ulProgressMax,ULONG ulStatusCode, LPCWSTR szStatusText);
        STDMETHODIMP OnDataAvailable(DWORD grfBSCF, DWORD dwSize, FORMATETC *pfmtetc,STGMEDIUM* pstgmed);
        STDMETHODIMP OnObjectAvailable(REFIID riid, IUnknown* punk);
        STDMETHODIMP OnLowResource(DWORD dwReserved);
        STDMETHODIMP OnStopBinding(HRESULT hrStatus, LPCWSTR szText);

        LPBINDSTATUSCALLBACK lpfnCB;
        PSTR sURL;
        PSTR sFile;
  char cSysDir[MAX_PATH];
  DWORD dwPlatform;
};