HttpSendRequest表示我的价值，而HttpSendRequestA则例外

Question

我想使用HttpSendRequest在C ++中发送POST值。我在https://requestbin.net上测试了请求我做了这个代码：

void sendValue()
{
    LPCSTR header = "Content-Type: application/x-www-form-urlencoded; charset=utf-8";
    std::string dataStr = u8"result=a very longue value !!!!!!!!!!!!!!!!!!!!!!!!!!!! :)";
    LPVOID myMessage = (LPVOID)dataStr.c_str();
    HINTERNET hInternet = InternetOpenA("InetURL/1.0", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
    HINTERNET hConnection = InternetConnectA(hInternet, "requestbin.net", 80, " ", " ", INTERNET_SERVICE_HTTP, 0, 1);
    HINTERNET hRequest = HttpOpenRequestA(hConnection, "POST", "/r/IDREQUESTBIN", NULL, NULL, NULL, 0, 1);
    HttpSendRequestA(hRequest, header, strlen(header), myMessage, dataStr.size());
    std::cout << "wcslen(header) " << strlen(header) << std::endl;
    std::cout << "dataStr.size() " << dataStr.size() << std::endl;
}

效果很好。我现在想使用wstring，我编写了此代码：

void sendValueV2()
{
    LPCWSTR header = L"Content-Type: application/x-www-form-urlencoded; charset=utf-8";
    std::wstring dataStr = L"result=a very longue value !!!!!!!!!!!!!!!!!!!!!!!!!!!! :)";
    LPVOID myMessage = (LPVOID)dataStr.c_str();
    HINTERNET hInternet = InternetOpen(L"InetURL/1.0", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
    HINTERNET hConnection = InternetConnect(hInternet, L"requestbin.net", 80, L" ", L" ", INTERNET_SERVICE_HTTP, 0, 1);
    HINTERNET hRequest = HttpOpenRequest(hConnection, L"POST", L"/r/IDREQUESTBIN", NULL, NULL, NULL, 0, 1);
    HttpSendRequest(hRequest, header, wcslen(header), myMessage, dataStr.size());
    std::wcout << "wcslen(header) " << wcslen(header) << std::endl;
    std::wcout << "dataStr.size() " << dataStr.size() << std::endl;
}

我的POST值被截断为：result=a very longue value !!

这是控制台的输出：

wcslen(header) 62
dataStr.size() 58
wcslen(header) 62
dataStr.size() 58

有人可以解释我发生了什么事？我快疯了。

Answer 1

根据documentation，dwOptional的HttpSendRequest参数以字节表示，而不是字符，因此替换：

HttpSendRequest(hRequest, header, wcslen(header), myMessage, dataStr.size());

with：
HttpSendRequest(hRequest, header, wcslen(header), myMessage, dataStr.size() * sizeof (WCHAR));

您的问题应得到解决。