在VC中WININET如何使用HTTP的POST方法

参考：微软的Knowledge Base的文章：“Q165298 OWTO: Simulate a Form POST Request Using WinInet”。
    该文章的主要内容如下：
    SUMMARY
    To properly simulate a Form submission using WinInet, you need to send a header that indicates the proper Content-Type. For Forms, the proper Content-Type header is: Content-Type: application/x-www-form-urlencoded
    
    MORE INFORMATION
    In many cases, the server does not respond appropriately if a Content-Type is not specified. For example, the Active Server Pages component of IIS 3.0 actually checks this header specifically for 'application/x-www-form- urlencoded' before adding form variables to the "Request.Form" object. This MIME/Content-Type indicates that the data of the request is a list of URL- encoded form variables. URL-encoding means that space character (ASCII 32) is encoded as '+', special character such '!' encoded in hexadecemal form as '%21'.
    
    Here is a snippet of code that uses the MFC WinInet classes to simulate a Form POST request:
     CString strHeaders =
     _T("Content-Type: application/x-www-form-urlencoded");
     // URL-encoded form variables -
     // name = "John Doe", userid = "hithere", other = "P&Q"
     CString strFormData = _T("name=John+Doe&userid=hithere&other=P%26Q");
    
     CInternetSession session;
     CHttpConnection* pConnection =
     session.GetHttpConnection(_T("ServerNameHere"));
     CHttpFile* pFile =
     pConnection->OpenRequest(CHttpConnection::HTTP_VERB_POST,
     _T("FormActionHere"));
     BOOL result = pFile->SendRequest(strHeaders,
     (LPVOID)(LPCTSTR)strFormData, strFormData.GetLength());
    
    
    Without MFC, the same code translates to straight SDK calls as follows:
     static TCHAR hdrs[] =
     _T("Content-Type: application/x-www-form-urlencoded");
     static TCHAR frmdata[] =
     _T("name=John+Doe&userid=hithere&other=P%26Q");
     statuc TCHAR accept[] =
     _T("Accept: */*");
    
     // for clarity, error-checking has been removed
     HINTERNET hSession = InternetOpen("MyAgent",
     INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
     HINTERNET hConnect = InternetConnect(hSession, _T("ServerNameHere"),
     INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
     HINTERNET hRequest = HttpOpenRequest(hConnect, "POST",
     _T("FormActionHere"), NULL, NULL, accept, 0, 1);
     HttpSendRequest(hRequest, hdrs, strlen(hdrs), frmdata, strlen(frmdata));
     // close any valid internet-handles