Question

我是C＃的新手，所以这可能非常明显，如何让这个工作或对我来说太复杂，但我正在尝试使用HtmlAgilityPack设置和抓取网页。目前我的代码编译但是当我写字符串时我只得到1个结果，它恰好是ul中li的最后一个结果。字符串拆分的原因是我最终可以将标题和描述字符串输出到.csv中以供进一步使用。我只是不确定下一步该做什么，为什么我要求提供任何帮助/理解/想法/想法/建议。谢谢！

    private void button1_Click(object sender, EventArgs e)
    {
        List<string> cities = new List<string>();
        //var xpath = "//h2[span/@id='Cities']";
        var xpath = "//h2[span/@id='Cities']" + "/following-sibling::ul[1]" + "/li";

        WebClient web = new WebClient();
        String html = web.DownloadString("http://wikitravel.org/en/Vietnam");

        hap.HtmlDocument doc = new hap.HtmlDocument();
        doc.LoadHtml(html);


        foreach (hap.HtmlNode node in doc.DocumentNode.SelectNodes(xpath)) 
        {
            string all = node.InnerText;

            //splits text between '—', '-' or ' ' into 2 parts
            string[] split = all.Split(new char[] { '—', ' ', '-' }, StringSplitOptions.None);

            string title;
            string description;

            int nodeCount;
            nodeCount = node.ChildNodes.Count;

            if (nodeCount == 2)
            {
                title = node.ChildNodes[0].InnerText;
                description = node.ChildNodes[1].InnerText;
            }
            else if (nodeCount == 4)
            {
                title = node.ChildNodes[0].InnerText;
                description = node.ChildNodes[1].InnerText + node.ChildNodes[2].InnerText;
            }
            else
            {
                title = "Error";
                description = "The node cound was not 2 or 3.  Check the div section.";
            }

            System.IO.StreamWriter write = new System.IO.StreamWriter(@"C:\Users\cbrannin\Desktop\textTest\testText.txt");
            write.WriteLine(all);

            write.Close();


        }

    }
}

Answer 1

一个问题是，每次循环都会覆盖输出文件。你可能想这样做：

using (StreamWriter write = new StreamWriter(@"filename"))
{
    foreach (hap.HtmlNode node in doc.DocumentNode.SelectNodes(xpath))
    {
        // do your thing
        write.WriteLine(all);
    }
}

另外，您是否已单步执行此操作，以查看您的HtmlNode来电中是否有多个SelectNode？

最后，我看不到你在title或description做了什么。你打算用别的东西吗？

使用HtmlAgilityPack的Web scraper

1 个答案: