Parsing html text into structure.

string url = "http://www.educationboardresults.gov.bd/arch/result.php?roll=" + roll + "&board=dhaka&exam=HSC&year=" + year;

for (i = startfrom; i <= endat; i++)
{
                HSC_WEB hw = new HSC_WEB(i, year);// This will download in separate thread and            
                hw.MyEvent += new HSC_WEB.ProgressDelegate(hw_Completed);// fire when finish
                TotalReq += 1;
................
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace HSC_RES_Downloader
{
    class stringsearch
    {
        public stringsearch( string  BaseString)
        {
            this.BaseString = BaseString;
        }
        public string BaseString;
        public string getyear()
        {
            return getstring(BaseString, "HSC", "", "Result");
        }
        public string getroll()
        {
            return getstring(BaseString, "Roll No.", "", "Registration");
        }
        public string getregno()
        {
            return getstring(BaseString, "Registration No.", "", "Academic Session");
        }
        public string getSession()
        {
            return getstring(BaseString, "Academic Session", "", "Name");
        }
        public string getname()
        {
            return getstring(BaseString, "Academic Session", "Name", "Father's Name");
        }
        public string getfname()
        {
            return getstring(BaseString, "Father's Name", "", "Institute");
        }
        public string getInstitutenane()
        {
            return getstring(BaseString, "Institute Name", "", "Center");
        }
        public string getCenter()
        {
            return getstring(BaseString, "Center Name", "", "Student Group");
        }
        public string getGroup()
        {
            return getstring(BaseString, "Student Group", "", "Student Type");
        }
        public string getsType()
        {
            return getstring(BaseString, "Student Type", "", "Result");
        }
        public string getResult()
        {
            return getstring(BaseString, "Student Type", "Result", "GPA");
        }
        public string getGPA()
        {
            return getstring(BaseString, "GPA", "", "Subject-wise");
        }

        public List<List<string>> subjectsgpa()
        { 
            List<string> sublist;
            
            string substr="BENGALI,ENGLISH,SECRETARIAL MANAGEMENT,COMMERCIAL GEOGRAPHY,"+
                    "STATISTICS,COMPUTER STUDIES,AGRICULTURE STUDIES," +
                    "PRINCIPLE OF BUSINESS,ACCOUNTING,"+
                    "PHYSICS,CHEMISTRY,MATHEMATICS,BIOLOGY,"+
                    "SOCIAL WELFARE,ISLAMIC HISTORY,ISLAMIC STUDIES,CIVICS";
            sublist = substr.Split(',').ToList();          
            
            int ps1 = 0;
            ps1 = BaseString.IndexOf("Code Subject Grade/ Marks");
            substr = BaseString.Substring(ps1 + "Code Subject Grade/ Marks".Length);
            string gpa=string.Empty ;
            List<List<string>> subgpas = new List<List<string>>();
            foreach (string SubName in sublist)
            {
                ps1 = substr.IndexOf(SubName);
                if (ps1 > 0)
                {
                    List<string> subgpa = new List<string>();
                    gpa = substr.Substring(ps1+SubName.Length,2);
                    subgpa.Add(gpa.Trim());
                    subgpa.Add( SubName);
                    subgpas.Add(subgpa);
                }
            }
            return  subgpas ;
        }

        public string getstring(string basestr, string str1, string str2, string endstring)
        {
            int ps1 = 0, ps2 = 0, ps3 = 0;
            ps1 = basestr.IndexOf(str1);
            ps2 = basestr.IndexOf(str2, ps1 + str1.Length);
            ps3 = basestr.IndexOf(endstring, ps2);
            string ss = basestr.Substring(ps2 + str2.Length, ps3 - ps2 - str2.Length);
            ss = ss.Trim();
            return ss;
        }

    }

}