vc++获取网页源码之使用import+接口方式

1.使用IWinHttpRequest获取网页源码

首先要创建基于对话框的mfc应用程序

2.import+接口方式

首先导入winhttp.dll,使用IWinHttpRequest接口

#import "C:\\Windows\\System32\\winhttp.dll"

void CHttpTestDlg::OnBnClickedButton1()
{
    ::CoInitialize(NULL); // 初始化com组件
    IWinHttpRequest *pHttpReq = NULL;

}

编译会出现如下错误:

在项目的Debug目录下,生成两个文件:winhttp.tlh和winhttp.tli

查看winhttp.tlh

解决方法:

1)使用命名空间WinHttp

2)在导入动态库的时候不要引入命名空间

代码:

#import "C:\\Windows\\System32\\winhttp.dll" no_namespace

// IID for IWinHttpRequest
const IID IID_IWinHttpRequest = 
{
    0x06f29373,
    0x5c5a,
    0x4b54,
    { 0xb0, 0x25, 0x6e, 0xf1, 0xbf, 0x8a, 0xbf, 0x0e }
};

void CHttpTestDlg::OnBnClickedButton1()
{
    HRESULT hr = NULL;
    hr = CoInitialize(NULL);
    IWinHttpRequest *pHttpReq = NULL;
     
    CLSID clsid;
    hr = CLSIDFromProgID(_T("WinHttp.WinHttpRequest.5.1"), &clsid);
    IID iid = __uuidof(IWinHttpRequest); 
    CLSID tclsid = __uuidof(WinHttpRequest);
        hr = CoCreateInstance(clsid, NULL, CLSCTX_INPROC_SERVER, IID_IWinHttpRequest, (LPVOID*)&pHttpReq);
    //hr = CoCreateInstance(__uuidof(WinHttpRequest), NULL, CLSCTX_INPROC_SERVER, __uuidof(IWinHttpRequest), (LPVOID*)&pHttpReq);

    if (FAILED(hr))
    {
        CoUninitialize();
        return;
    }

    hr = pHttpReq->Open(_T("GET"), _T("http://www.baidu.com")); //缺省值为vtMissing
    if (FAILED(hr))
    {
        pHttpReq->Release();
        CoUninitialize();
        return;
    }
        

    hr = pHttpReq->Send(); // 缺省值为vtMissing
    if (FAILED(hr))
    {
        pHttpReq->Release();
        CoUninitialize();
        return;
    }
    
    CString respStr = pHttpReq->ResponseText;
    MessageBox(respStr); 

    pHttpReq->Release();
    CoUninitialize();
}