xpath表达式从链接中选择href值

Posted 2021-03-28

我有这样的html代码

<a class="cat" href="/Home/txtdata0/">txtdata0</a>
<a class="cat" href="/Home/txtdata1/">txtdata1</a>
<a class="cat" href="/Home/txtdata2/">txtdata2</a>
<a class="cat" href="/Home/txtdata3/">txtdata3</a>

访问链接的所有文本我使用这样的XPATH（如在C＃中的Visual Studio中）

.//a[@class="cat"]

访问链接的所有href值我使用这样的XPATH（如在C＃中的Visual Studio中）

.//a[@class="cat"]/@href

谷歌Chrome Xpath助手秀（.//a[@class="cat“]和.//a[@class="cat"]/@href)两个结果都是正确的

txtdata0
txtdata1
txtdata2
txtdata3

和

/Home/txtdata0/
/Home/txtdata1/
/Home/txtdata2/
/Home/txtdata3/

带有这样的Xpath的Visual Studio //一个[@class = “cat ”]显示：

txtdata0
txtdata1
txtdata2
txtdata3

和这样的Xpath .//a[@class="cat"]/@href显示：

txtdata0
txtdata1
txtdata2
txtdata3

为什么第二输出与第一输出相同？

程序代码

HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(seturl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
    Stream receiveStream = response.GetResponseStream();
    StreamReader readStream = null;

    if (response.CharacterSet == null)
    {
        readStream = new StreamReader(receiveStream);
    }
    else
    {
        readStream = new StreamReader(receiveStream, Encoding.GetEncoding(response.CharacterSet));
    }

    data = readStream.ReadToEnd();

    response.Close();
    readStream.Close();
}

doc.LoadHtml(data);

HtmlAgilityPack.HtmlNodeCollection bodynode = doc.DocumentNode.SelectNodes(".//a[@class="cat"]");
HtmlAgilityPack.HtmlNodeCollection bodynod = doc.DocumentNode.SelectNodes(".//a[@class="cat"]/@href");
MessageBox.Show(bodynode.Count.ToString());
MessageBox.Show(bodynod.Count.ToString());

for (int i = 0; i < bodynode.Count; i++)
{
    MessageBox.Show(bodynode[i].InnerText.ToString() + " - " + bodynod[i].InnerText.ToString());
}

答案

如果我没记错的话可以像这样提取HAP属性

 string _tmpUrl = documentUrl.DocumentNode.SelectNodes("//a[@class='cat']")[i].Attributes["href"].Value;