Linq all operations

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class _Default : System.Web.UI.Page
{
//    DataClassesDataContext linq = new DataClassesDataContext();
       DataClassesDataContext linq=new DataClassesDataContext();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            fill();
            Fill_drop();
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        tbl_reg t = new tbl_reg();
        t.username = txtname.Text;
        t.password = txtpwd.Text;
        //tbl_data t1 = new tbl_data();
        //t1.Uname = txtname.Text;
        //t1.Password = txtpwd.Text;
        linq.tbl_regs.InsertOnSubmit(t);
        linq.SubmitChanges();
        fill();
        Fill_drop();
        clear();
    }

    public void Fill_drop()
    {
        //var v = from l in linq.tbl_datas select l;

        //drplist.DataSource = v;
        //drplist.DataTextField = "Uname";
        //drplist.DataValueField = "Id";
        //drplist.DataBind();
        //drplist.Items.Insert(0, new ListItem("Select Name"));
    }

    public void clear()
    {
        txtname.Text = "";
        txtpwd.Text = "";
    }

    public void fill()
    {
        var str = from l in linq.tbl_regs select l;
        GridView1.DataSource = str;
        GridView1.DataBind();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        int id = int.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
        TextBox txtuname = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtuname");
        TextBox txtpassword = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtpassword");
        tbl_reg t1 = linq.tbl_regs.Single(a => a.id == id);
        t1.username = txtuname.Text;
        t1.password = txtpassword.Text;
        linq.SubmitChanges();
        GridView1.EditIndex = -1;
        fill();

    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        fill();
    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        fill();
    }
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int id = int.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
        tbl_reg t1 = linq.tbl_regs.Single(a => a.id == id);
        linq.tbl_regs.DeleteOnSubmit(t1);
        linq.SubmitChanges();
        fill();
}
    protected void  btn_select_Click(object sender, EventArgs e)
{
    var ds = from d in linq.tbl_regs

             orderby d.id descending
             select d;
              //  select new { d.id, d.password, d.username };
        GridView2.DataSource = ds;
        GridView2.DataBind();
       
}
protected void  btn_update_Click(object sender, EventArgs e)
{//Select from text box
        int n = int.Parse(txtpwd.Text.ToString());
        var ds =from d in linq.tbl_regs
                  where d.id == n
                  select d;
        GridView2.DataSource = ds;
        GridView2.DataBind();

}
}

String Manupulation operations

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

namespace LInq_Example
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] s = new string[] { "one","two","three","four","five","six","Seven","Eight","Nine","Ten"};
            string[] ss = {"oo","one","two","three","eight" };
            var n = from str in s
                where str.Length<10
                orderby str.Length
                 orderby str
                 select str;
            //join query
                   //from str in s
                   //join str1 in ss
                   //on str equals str1
                   //select new { str, str1 };
            foreach (var item in n)
            {
                Console.WriteLine(item);
            }
            Console.ReadLine();
        }
    }
}

Parallel Linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;

namespace plinq123
{
    class Program
    {
        static void Main(string[] args)
        {
            Task.Factory.StartNew(() => NormalMethod());
            Console.ReadLine();
        }
        public static void NormalMethod()
        {
            int[] n = Enumerable.Range(1, 10000000).ToArray();
            Stopwatch s = new Stopwatch();
           
            s.Start();
            var count = (from v in n
                        where v % 11 == 0
                        orderby v descending
                        select v).ToArray();
            s.Stop();

            Console.WriteLine("The total numbers divisible by 2 are "+count.Count()+" in "+s.ElapsedMilliseconds+" Milliseconds");
                       
            s.Restart();           
            var count1 = (from v in n.AsParallel()
                        where v % 11 == 0
                        orderby v descending
                        select v).ToArray();
            s.Stop();

            Console.WriteLine("The total numbers divisible by 2 are " + count1.Count() + " in " + s.ElapsedMilliseconds + " Milliseconds");
       
        }
    }
}
Output: