//Read Data From this website : http://csharp.net-informations.com/xml/how-to-read-xml.htm

//http://dotnetqueries.com/Article/158/how-to-read-data-from-xml-file-in-c

using System;

using System.Data;

using System.Xml;

using System.IO;

using System.Net;

public class Program

{

    public static void Main()

    {

             var client = new WebClient();

            client.Headers.Add("User-Agent", "C# console program");

            string url = "https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/123113/xrefs/PatentID/TXT";

            string content = client.DownloadString(url);

​

            Console.WriteLine(content);

           XmlDataDocument xmldoc = new XmlDataDocument();

            XmlNodeList xmlnode ;

            int i = 0;

            string str = null;

           // FileStream fs = new FileStream("http://vb.net-informations.com/xml/img/product.xml", FileMode.Open, FileAccess.Read);

            xmldoc.Load("https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/patent/KR-20200026854-A/XML/");

            xmlnode = xmldoc.GetElementsByTagName("Information");

                str =xmlnode[4].ChildNodes.Item(1).InnerText.Trim() + "  " + xmlnode[4].ChildNodes.Item(2).InnerText.Trim();

                if(str.Contains("Priority Date"))

                    Console.WriteLine(str);            

    }

}