UrlToDownloadFile 函数不下载

Question

我正在使用 UrlToDownloadFile 函数，但它没有下载文件。编译器中没有显示错误（使用 VStudio 2012）

代码如下：

#include <Windows.h>
#include "urlmon.h"

#pragma lib "urlmon.lib"

using namespace std;

void dwFile();


int _tmain(int argc, _TCHAR* argv[])
{
    dwFile ();
    return 0;
}

void dwFile () 
{
    LPCSTR url = ("http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf");
    LPCSTR fPath = ("C:\Users\Andyy\Desktop\test\n3337.pdf");

    HRESULT URLDownloadToFile ((NULL, url, fPath, 0, NULL));
}

Answer 1

您的代码没有进行任何错误处理，您的字符串处理有误。改用这个：

#include <Windows.h>
#include "urlmon.h"

#pragma lib "urlmon.lib"

using namespace std;

void dwFile();

int _tmain(int argc, _TCHAR* argv[])
{
    dwFile ();
    return 0;
}

void dwFile () 
{
    LPCTSTR url = TEXT("http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf");
    LPCTSTR fPath = TEXT("C:\Users\Andyy\Desktop\test\n3337.pdf");

    HRESULT hr = URLDownloadToFile (NULL, url, fPath, 0, NULL);
    if (FAILED(hr))
    {
        // do something ...
    }

    /* or more preffered:

    LPCWSTR url = L"http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf";
    LPCWSTR fPath = L"C:\Users\Andyy\Desktop\test\n3337.pdf");

    HRESULT hr = URLDownloadToFileW (NULL, url, fPath, 0, NULL);
    if (FAILED(hr))
    {
        // do something ...
    }
    */
}

请注意文档中的以下注释：

URLDownloadToFile returns S_OK even if the file cannot be created and the download is canceled. If the szFileName parameter contains a file path, ensure that the destination directory exists before calling URLDownloadToFile. For best control over the download and its progress, an IBindStatusCallback interface is recommended.

UrlToDownloadFile 函数不下载

UrlToDownloadFile function not downloading

c++

msdn

urlmon