Using XPath and WebBrowser Control to select multiple nodes

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In C# WinForms sample application I have used WebBrowser control and JavaScript-XPath to select single node and change that node .innerHtml by the following code:

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别跟我提以往

2020-12-16 09:41

I have found solution, here is the code:

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;
            }
        }
    }

}
}

And here are the code running results:

Code running results

I have put credits' references to my code inline. If you'll find I have missed some please point me in your comments and I will add them.

If you know better solution - shorter code, more effective code - please comment and/or post your answer.

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