Pasted

using System;
using System.Linq;
using Aspose.Html;
using Aspose.Html.Collections;
using Aspose.Html.Dom;
using Aspose.Html.Dom.Traversal;
using Aspose.Html.Dom.Traversal.Filters;
 
namespace Task982
{
    class Program
    {
        private static HTMLDocument _document;
 
        private static string Tabs(int n)
        {
            return new string('\t', n);
        }
        static void Main(string[] args)
        {
            const string url = @"http://asposedemo20170904120448.azurewebsites.net/home/QuerySelector";            
            try
            {
                _document = new HTMLDocument(url);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                return;
            }
            Demo01();
            Demo02();
            Demo03();
            Demo04();
            Demo05();
            Demo06();
        }
 
        private static void Demo01()
        {
            var elementById = _document.GetElementById("Listfriends");
            var elementBySelector = _document.QuerySelector("#Listfriends");
            Console.WriteLine($"Listfriends is {elementById.TagName}");
            Console.WriteLine($"Listfriends is {elementBySelector.TagName}");
        }
 
        private static void Demo02()
        {
            var inputs = _document.GetElementsByTagName("input");
            Console.WriteLine($"We have a {inputs.Length} inputs");
            //var radiosGroup = _document.GetElementsByName("rr");
            //Console.WriteLine($"We have {radiosGroup.Length} radio");
            var unorderedList = _document.QuerySelectorAll("ul");
            Console.WriteLine($"We have a {unorderedList.Length} ULs");
        }
 
        private static void Demo03()
        {
            var links = _document.Links;
            Console.WriteLine($"We have a {links.Length} links.");
            var forms = _document.Forms;            
            Console.WriteLine($"We have a {forms.Length} forms.");
        }
 
        private static void Demo04()
        {
            var elementById = _document.GetElementById("Listfriends");
            var elementsByClassName = _document.GetElementsByClassName("intro").First();
            var elementsByTagName = _document.GetElementsByTagName("h4").First();
            Console.WriteLine($"Element found by Id:{elementById.TagName}"); //UL
            Console.WriteLine($"First element found by class name:{elementsByClassName.TagName}"); //DIV
            Console.WriteLine($"First element found by tag name:{elementsByTagName.TagName}"); //H4
        }
 
        private static void Demo05()
        {
            var element1 = _document.GetElementById("Listfriends");
            element1.SetAttribute("class", "newsletter");
 
            var element2 = _document.QuerySelector("#Listfriends");
            element2.SetAttribute("class", "newsletter");
 
            var elements3 = _document.GetElementsByTagName("p");
            foreach (var element in elements3)
            {
                element.SetAttribute("class", "newsletter");
            }
            var elements4 = _document.QuerySelectorAll("p");
            foreach (var element in elements4)
            {
                element.SetAttribute("class", "newsletter");
            }
        }
 
        private static void Demo06()
        {
            // Select by matching 'class' attributes.intro
            var element3 = _document.QuerySelector(".intro");
            Console.WriteLine(element3.TagName); // DIV
 
            //Select by matching 'id' attributes Lastname
            var element4 = _document.QuerySelector("#Lastname");
            Console.WriteLine(element4.TagName); //SPAN
 
            //Select by finding direct children 
            var collection5 = _document.QuerySelectorAll("ul>li");
            Console.WriteLine(collection5.Length); //4
 
            //Descendent Select by finding all decedents div p
            var collection6 = _document.QuerySelectorAll("div p");
            Console.WriteLine(collection6.Length); //4
 
            //Sibling Selects nearest next sibling h1+p
            var collection7 = _document.QuerySelectorAll("ul+h3");
            Console.WriteLine(collection7.Length); //1
 
            //Attribute Selects based on an attribute and or its value  input[type = 'button']
            var collection8 = _document.QuerySelectorAll("input[type = 'checkbox']");
            foreach (var element in collection8)
            {
                Console.WriteLine(element.Id); //cc1 cc2 cc3
            }
            Console.WriteLine(collection8.Length); //3
 
            //Selects based on a CSS selector: psuedo class ul : first-child
            var collection9 = _document.QuerySelector("p:first-child");
            Console.WriteLine(collection9.TextContent); // My name is Donald Duck 
        }
    }
}