C# 使用XPath和WebBrowser控件选择多个节点_C#_Javascript_Xpath_Webbrowser Control_Evaluate

C# 使用XPath和WebBrowser控件选择多个节点

c# javascript xpath

C# 使用XPath和WebBrowser控件选择多个节点,c#,javascript,xpath,webbrowser-control,evaluate,C#,Javascript,Xpath,Webbrowser Control,Evaluate,在C#WinForms示例应用程序中，我使用WebBrowser控件和选择单个节点并通过以下代码更改该节点。innerHtml： private void MainForm_Load(object sender, EventArgs e) { webBrowser1.DocumentText = @" <html> <head> <script src="

在C#WinForms示例应用程序中，我使用WebBrowser控件和选择单个节点并通过以下代码更改该节点。innerHtml：

    private void MainForm_Load(object sender, EventArgs e)
    {
        webBrowser1.DocumentText = @"
            <html>
            <head>
                <script src=""http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js""></script>
            </head>
            <body>
            <img alt=""0764547763 Product Details"" 
                src=""http://ecx.images-amazon.com/images/I/51AK1MRIi7L._AA160_.jpg"">
            <hr/>
            <h2>Product Details</h2>
            <ul>
            <li><b>Paperback:</b> 648 pages</li>
            <li><b>Publisher:</b> Wiley; Unlimited Edition edition (October 15, 2001)</li>
            <li><b>Language:</b> English</li>
            <li><b>ISBN-10:</b> 0764547763</li>
            </ul>
            </body>
            </html>
        ";
    }

    private void cmdTest_Click(object sender, EventArgs e)
    {
        string xPath = "//li";
        string code = string.Format("document.evaluate('{0}', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;", xPath);
        var li = webBrowser1.Document.InvokeScript("eval", new object[] { code }) as mshtml.IHTMLElement;

        li.innerHTML = string.Format("<span style='text-transform: uppercase;font-family:verdana;color:green;'>{0}</span>", li.innerText);

    }

但是

allLI

变量的返回值是

NULL

如果我写信

        xPath = "//ul//*";
        code = string.Format("document.evaluate('{0}', document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null);", xPath);
        var allLI = webBrowser1.Document.InvokeScript("eval", new object[] { code });

然后返回的

allLI

变量不为null，其值类型为

COM对象

，但我不清楚该

COM对象

可以转换为哪种更具体的类型

有没有一种方法可以通过此处使用的技术选择多个节点

[编辑]

xPath=“ul/*”

到

xPath=“///ul//*”

[添加]

我在示例HTML中添加了两个javaScript函数：

<script type=""text/javascript"">
    function GetElementsText (XPath) {
            var xPathRes = document.evaluate ( XPath, document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null);              
            var nextElement = xPathRes.iterateNext ();
            var text = """";
            while (nextElement) {
               text += nextElement.innerText;
               nextElement = xPathRes.iterateNext ();
            }
        return text;
        };

    function GetElements (XPath) {
            var xPathRes = document.evaluate ( XPath, document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null);              
            var nextElement = xPathRes.iterateNext ();
            var elements = new Object();
            var elementIndex = 1;
            while (nextElement) {
               elements[elementIndex++] = nextElement;
               nextElement = xPathRes.iterateNext ();
            }
        return elements;
        };
</script>

我正在获取所有

li

元素的文本：

"Paperback: 648 pages \r\nPublisher: Wiley; Unlimited Edition edition (October 15, 2001) \r\nLanguage: English \r\nISBN-10: 0764547763 "

当我在

cmd\u TestClick

方法中运行以下C#代码行时：

var text = webBrowser1.Document.InvokeScript("eval", new object[] { "GetElementsText('//ul')" });

var elements = webBrowser1.Document.InvokeScript("eval", new object[] { "GetElements('//ul')" });

我正在获取

COM对象

，无法将其转换为

IEnumerable

有没有办法在C代码中处理由返回的HTML节点的javaScript集合

var elements = webBrowser1.Document.InvokeScript("eval", new object[] { "GetElements('//ul')" });

？

我找到了解决方案，下面是代码：

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Windows.Forms;

namespace myTest.WinFormsApp
{
public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
    }

    private void MainForm_Load(object sender, EventArgs e)
    {
        webBrowser1.DocumentText = @"
            <html>
            <body>
            <img alt=""0764547763 Product Details"" 
                src=""http://ecx.images-amazon.com/images/I/51AK1MRIi7L._AA160_.jpg"">
            <hr/>
            <h2>Product Details</h2>
            <ul>
            <li><b>Paperback:</b> 648 pages</li>
            <li><b>Publisher:</b> Wiley; Unlimited Edition edition (October 15, 2001)</li>
            <li><b>Language:</b> English</li>
            <li><b>ISBN-10:</b> 0764547763</li>
            </html>
        ";
    }

    private void cmdTest_Click(object sender, EventArgs e)
    {
        var processor = new WebBrowserControlXPathQueriesProcessor(webBrowser1);

        // change attributes of the first element of the list
        {
            var li = processor.GetHtmlElement("//li");
            li.innerHTML = string.Format("<span style='text-transform: uppercase;font-family:verdana;color:green;'>{0}</span>", li.innerText);
        }

        // change attributes of the second and subsequent elements of the list
        var list = processor.GetHtmlElements("//ul//li");
        int index = 1;
        foreach (var li in list)
        {
            if (index++ == 1) continue;
            li.innerHTML = string.Format("<span style='text-transform: uppercase;font-family:verdana;color:blue;'>{0}</span>", li.innerText);
        }

    }

    /// <summary>
    /// Enables IE WebBrowser control to evaluate XPath queries 
    /// by injecting http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js
    /// and to return XPath queries results to the calling C# code as strongly typed
    /// mshtml.IHTMLElement and IEnumerable<mshtml.IHTMLElement>
    /// </summary>
    public class WebBrowserControlXPathQueriesProcessor
    {
        private System.Windows.Forms.WebBrowser _webBrowser;
        public WebBrowserControlXPathQueriesProcessor(System.Windows.Forms.WebBrowser webBrowser)
        {
            _webBrowser = webBrowser;
            injectScripts();
        }

        private void injectScripts()
        {
            // Thanks to: http://stackoverflow.com/questions/7998996/how-to-inject-javascript-in-webbrowser-control

            HtmlElement head = _webBrowser.Document.GetElementsByTagName("head")[0];
            HtmlElement scriptEl = _webBrowser.Document.CreateElement("script");
            mshtml.IHTMLScriptElement element = (mshtml.IHTMLScriptElement)scriptEl.DomElement;
            element.src = "http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js";
            head.AppendChild(scriptEl);

            string javaScriptText = @"
                    function GetElements (XPath) {
                            var xPathRes = document.evaluate ( XPath, document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null);              
                            var nextElement = xPathRes.iterateNext ();
                            var elements = new Object();
                            var elementIndex = 1;
                            while (nextElement) {
                            elements[elementIndex++] = nextElement;
                            nextElement = xPathRes.iterateNext ();
                            }
                        elements.length = elementIndex -1;
                        return elements;
                        };
                   ";
            scriptEl = _webBrowser.Document.CreateElement("script");
            element = (mshtml.IHTMLScriptElement)scriptEl.DomElement;
            element.text = javaScriptText;
            head.AppendChild(scriptEl);
        }

        /// <summary>
        /// Gets Html element's mshtml.IHTMLElement object instance using XPath query
        /// </summary>
        public mshtml.IHTMLElement GetHtmlElement(string xPathQuery)
        {
            string code = string.Format("document.evaluate('{0}', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;", xPathQuery);
            return _webBrowser.Document.InvokeScript("eval", new object[] { code }) as mshtml.IHTMLElement;
        }

        /// <summary>
        /// Gets Html elements' IEnumerable<mshtml.IHTMLElement> object instance using XPath query
        /// </summary>
        public IEnumerable<mshtml.IHTMLElement> GetHtmlElements(string xPathQuery)
        {
            // Thanks to: http://stackoverflow.com/questions/5278275/accessing-properties-of-javascript-objects-using-type-dynamic-in-c-sharp-4
            var comObject = _webBrowser.Document.InvokeScript("eval", new object[] { string.Format("GetElements('{0}')", xPathQuery) });
            Type type = comObject.GetType();
            int length = (int)type.InvokeMember("length", BindingFlags.GetProperty, null, comObject, null);

            for (int i = 1; i <= length; i++)
            {
                yield return type.InvokeMember(i.ToString(), BindingFlags.GetProperty, null, comObject, null) as mshtml.IHTMLElement;
            }
        }
    }

}
}

使用系统；
使用System.Collections.Generic；
运用系统反思；
使用System.Windows.Forms；
命名空间myTest.WinFormsApp
{
公共部分类主窗体：窗体
{
公共表格（
{
初始化组件（）；
}
私有void主窗体加载（对象发送方、事件参数e）
{
webBrowser1.DocumentText=@“

产品详情

平装本：648页
出版商：Wiley；无限版（2001年10月15日）
语言：英语
ISBN-10:0764547763
";
}
私有void cmdTest_单击（对象发送方，事件参数e）
{
var处理器=新的WebBrowserControlXPathQueriesProcessor（webBrowser1）；
//更改列表第一个元素的属性
{
var li=processor.GetHtmlElement（“//li”）；
li.innerHTML=string.Format（“{0}”，li.innerText）；
}
//更改列表第二个和后续元素的属性
var list=processor.GetHtmlElements（“//ul//li”）；
int指数=1；
foreach（列表中的变量li）
{
如果（索引+++==1）继续；
li.innerHTML=string.Format（“{0}”，li.innerText）；
}
}
/// 
///启用IE WebBrowser控件以计算XPath查询
///注入http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js
///并将XPath查询结果作为强类型返回给调用C#代码
///mshtml.IHTMLElement和IEnumerable
/// 
公共类WebBrowserControlXPathQueriesProcessor
{
private System.Windows.Forms.WebBrowser\u WebBrowser；
公共WebBrowserControlXPathQueriesProcessor（System.Windows.Forms.WebBrowser WebBrowser）
{
_webBrowser=webBrowser；
注入脚本（）；
}
私有脚本（）
{
//感谢：http://stackoverflow.com/questions/7998996/how-to-inject-javascript-in-webbrowser-control
HtmlElement head=_webBrowser.Document.GetElementsByTagName（“head”）[0]；
HtmlElement scriptEl=_webBrowser.Document.CreateElement（“脚本”）；
mshtml.IHTMLScriptElement=（mshtml.IHTMLScriptElement）scriptEl.doelement；
element.src=”http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js";
头.附肢儿童（scriptEl）；
字符串javaScriptText=@”
函数GetElements（XPath）{
var xPathRes=document.evaluate（XPath，document，null，XPathResult.ORDERED\u NODE\u ITERATOR\u TYPE，null）；
var nextElement=xPathRes.iterateNext（）；
var元素=新对象（）；
var elementIndex=1；
while（nextElement）{
元素[elementIndex++]=nextElement；
nextElement=xPathRes.iterateNext（）；
}
elements.length=elementIndex-1；
返回元素；
};
";
scriptEl=_webBrowser.Document.CreateElement（“脚本”）；
元素=（mshtml.IHTMLScriptElement）scriptEl.doElement；
element.text=javaScriptText；
头.附肢儿童（scriptEl）；
}
/// 
///使用XPath查询获取Html元素的mshtml.IHTMLElement对象实例
/// 
public mshtml.IHTMLElement GetHtmlElement（字符串xPathQuery）
{
string code=string.Format（“document.evaluate（{0}），document，null，XPathResult.FIRST\u ORDERED\u NODE\u TYPE，null）。singleNodeValue；”，xPathQuery）；
将_webBrowser.Document.InvokeScript（“eval”，新对象[]{code}）作为mshtml.IHTMLElement返回；
}
/// 
///使用XPath查询获取Html元素的IEnumerable对象实例
/// 
公共IEnumerable GetHtmlElements（字符串xPathQuery）
{
//感谢：http://stackoverflow.com/questions/5278275/accessing-properties-of-javascript-objects-using-type-dynamic-in-c-sharp-4
var comObject=_webBrowser.Document.InvokeScript（“eval”，新对象[]{string.Format（“GetElements（{0}'）”，xPathQuery）}）；
Type Type=comObject.GetType（）；
int length=（int）type.InvokeMember（“长度”，BindingFlags.GetProperty，null，comObject，null）；
对于（inti=1；我能帮上忙吗？@Noseratio：我想避免使用HTML敏捷包-我想直接使用
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Windows.Forms;

namespace myTest.WinFormsApp
{
public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
    }

    private void MainForm_Load(object sender, EventArgs e)
    {
        webBrowser1.DocumentText = @"
            <html>
            <body>
            <img alt=""0764547763 Product Details"" 
                src=""http://ecx.images-amazon.com/images/I/51AK1MRIi7L._AA160_.jpg"">
            <hr/>
            <h2>Product Details</h2>
            <ul>
            <li><b>Paperback:</b> 648 pages</li>
            <li><b>Publisher:</b> Wiley; Unlimited Edition edition (October 15, 2001)</li>
            <li><b>Language:</b> English</li>
            <li><b>ISBN-10:</b> 0764547763</li>
            </html>
        ";
    }

    private void cmdTest_Click(object sender, EventArgs e)
    {
        var processor = new WebBrowserControlXPathQueriesProcessor(webBrowser1);

        // change attributes of the first element of the list
        {
            var li = processor.GetHtmlElement("//li");
            li.innerHTML = string.Format("<span style='text-transform: uppercase;font-family:verdana;color:green;'>{0}</span>", li.innerText);
        }

        // change attributes of the second and subsequent elements of the list
        var list = processor.GetHtmlElements("//ul//li");
        int index = 1;
        foreach (var li in list)
        {
            if (index++ == 1) continue;
            li.innerHTML = string.Format("<span style='text-transform: uppercase;font-family:verdana;color:blue;'>{0}</span>", li.innerText);
        }

    }

    /// <summary>
    /// Enables IE WebBrowser control to evaluate XPath queries 
    /// by injecting http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js
    /// and to return XPath queries results to the calling C# code as strongly typed
    /// mshtml.IHTMLElement and IEnumerable<mshtml.IHTMLElement>
    /// </summary>
    public class WebBrowserControlXPathQueriesProcessor
    {
        private System.Windows.Forms.WebBrowser _webBrowser;
        public WebBrowserControlXPathQueriesProcessor(System.Windows.Forms.WebBrowser webBrowser)
        {
            _webBrowser = webBrowser;
            injectScripts();
        }

        private void injectScripts()
        {
            // Thanks to: http://stackoverflow.com/questions/7998996/how-to-inject-javascript-in-webbrowser-control

            HtmlElement head = _webBrowser.Document.GetElementsByTagName("head")[0];
            HtmlElement scriptEl = _webBrowser.Document.CreateElement("script");
            mshtml.IHTMLScriptElement element = (mshtml.IHTMLScriptElement)scriptEl.DomElement;
            element.src = "http://svn.coderepos.org/share/lang/javascript/javascript-xpath/trunk/release/javascript-xpath-latest-cmp.js";
            head.AppendChild(scriptEl);

            string javaScriptText = @"
                    function GetElements (XPath) {
                            var xPathRes = document.evaluate ( XPath, document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, null);              
                            var nextElement = xPathRes.iterateNext ();
                            var elements = new Object();
                            var elementIndex = 1;
                            while (nextElement) {
                            elements[elementIndex++] = nextElement;
                            nextElement = xPathRes.iterateNext ();
                            }
                        elements.length = elementIndex -1;
                        return elements;
                        };
                   ";
            scriptEl = _webBrowser.Document.CreateElement("script");
            element = (mshtml.IHTMLScriptElement)scriptEl.DomElement;
            element.text = javaScriptText;
            head.AppendChild(scriptEl);
        }

        /// <summary>
        /// Gets Html element's mshtml.IHTMLElement object instance using XPath query
        /// </summary>
        public mshtml.IHTMLElement GetHtmlElement(string xPathQuery)
        {
            string code = string.Format("document.evaluate('{0}', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;", xPathQuery);
            return _webBrowser.Document.InvokeScript("eval", new object[] { code }) as mshtml.IHTMLElement;
        }

        /// <summary>
        /// Gets Html elements' IEnumerable<mshtml.IHTMLElement> object instance using XPath query
        /// </summary>
        public IEnumerable<mshtml.IHTMLElement> GetHtmlElements(string xPathQuery)
        {
            // Thanks to: http://stackoverflow.com/questions/5278275/accessing-properties-of-javascript-objects-using-type-dynamic-in-c-sharp-4
            var comObject = _webBrowser.Document.InvokeScript("eval", new object[] { string.Format("GetElements('{0}')", xPathQuery) });
            Type type = comObject.GetType();
            int length = (int)type.InvokeMember("length", BindingFlags.GetProperty, null, comObject, null);

            for (int i = 1; i <= length; i++)
            {
                yield return type.InvokeMember(i.ToString(), BindingFlags.GetProperty, null, comObject, null) as mshtml.IHTMLElement;
            }
        }
    }

}
}