用ShellExecute打开一个下载链接，如何判断下载完成

在程序中用ShellExecute打开了一个超链接，想要等点击下载，确定以后弹出下载成功对话框，可是不知道怎么判断结束 ，这样写也不行，打开链接就返回了，求助，急急急
SHELLEXECUTEINFO ShExecInfo={0};
ShExecInfo.cbSize=sizeof(SHELLEXECUTEINFO);
ShExecInfo.fMask=SEE_MASK_NOCLOSEPROCESS;
ShExecInfo.hwnd=NULL;
ShExecInfo.lpVerb=_T("open");
ShExecInfo.lpFile=L"http://www.aec188.com/download/homecost/homecost.xls";
ShExecInfo.lpParameters=_T("");
ShExecInfo.lpDirectory=NULL;
ShExecInfo.nShow=SW_SHOWNORMAL;
ShExecInfo.hInstApp=NULL;
ShellExecuteEx(&ShExecInfo);
WaitForSingleObject(ShExecInfo.hProcess, INFINITE);
CTemp_Information Temp_InformationLoadSuccess(TempExcDlgEnum::LoadSuccess);
Temp_InformationLoadSuccess.DoModal();