Async Register client script

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication2
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
           

            Task task = new Task(ProcessDataAsync);
            task.Start();
           
            //task.Wait();


            string sd = "window.open('webform2.aspx', '_blank', 'toolbar=yes,scrollbars=yes,resizable=yes,top=500,left=500,width=400,height=400')";
            ScriptManager.RegisterStartupScript(this, GetType(), "kkk", sd, true);
           
        }

        private async void ProcessDataAsync()
        {
            int count = 0;
            using (StreamReader reader = new StreamReader("D:\\enable1.txt"))
            {
                string v = await reader.ReadToEndAsync();

                // ... Process the file data somehow.
                count += v.Length;

                // ... A slow-running computation.
                //     Dummy code.
                for (int i = 0; i < 10000; i++)
                {
                    int x = v.GetHashCode();
                    if (x == 0)
                    {
                        count--;
                    }
                }
            }
        }
    }
}

SQL to XLS

using System.Data;
using System.Data.SqlClient;
using System.IO;

public partial class Sql2Xl : System.Web.UI.Page
{
    SqlConnection cn = new SqlConnection("data source=SRIKANTA-PC\\SQLEXPRESS;initial catalog=adi;user id=sa;password=banka");
    protected void Page_Load(object sender, EventArgs e)
    {
        if (ConnectionState.Closed == cn.State)
        {
            cn.Open();
        }

    }

   
    protected void Button1_Click(object sender, EventArgs e)
    {
        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter("select * from student", cn);
        da.Fill(ds);
        ds.WriteXml(Server.MapPath(".") + "/abc.xml");

        File.Move(Server.MapPath(".") + "/abc.xml", Server.MapPath(".") + "/demo.xls");

       
    }
}

Get Selected Row Values of a GridView on Client Side using JavaScript

-------------------------------------GRIDPAGE.ASPX--------------------------------------

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {

        if (e.Row.RowType == DataControlRowType.DataRow)
        {
             
            e.Row.Attributes["onclick"] = "GetRowValue(this);"; 
        }


    }

Add a server variable:

<asp:HiddenField ID="hdnSelected" runat="server" />

Add a Style

<style>
        .AquaMarine {
            background-color: red;
        }
    </style>
--------------------------------------GRIDPAGE.ASPX----------------------------------

function GetRowValue(obj) {
            obj.className = 'AquaMarine';
       
            var curRow = parseInt(obj.rowIndex);

            var grid = document.getElementById("<%= GridView1.ClientID %>");

            for (i = 1; i < grid.rows.length; i++) {
                if(i != curRow)
                grid.rows[i].style.backgroundColor = '#ffffff';
            }

            //Initialize hidden filed value
            document.getElementById('<%=hdnRowValues.ClientID%>').value = '';
            //Set values from the row to hidden field.
            for(j=1;j<grid.rows[curRow].cells.length;j++)
            {
             
                cell = grid.rows[curRow].cells[j];
                document.getElementById('<%=hdnRowValues.ClientID%>').value = document.getElementById('<%=hdnRowValues.ClientID%>').value + cell.innerText + ',';
                }
         
              _selectedRowValue = document.getElementById('<%=hdnRowValues.ClientID%>').value;
        }

---------------------------------------------------------------

sql to excel

http://www.aspsnippets.com/Articles/Export-data-from-SQL-Server-to-Excel-in-ASPNet-using-C-and-VBNet.aspx

Select Some Checkboxes

Javascript

-----------------------------------------------------------------------------------
    function AddRemoveSelected(obj, studId) {

            //debugger;

            if (obj.checked == true) {
                document.getElementById('<%=hdnSelected.ClientID%>').value = document.getElementById('<%=hdnSelected.ClientID%>').value + ',' + studId;
            }
            else {
                document.getElementById('<%=hdnSelected.ClientID%>').value = document.getElementById('<%=hdnSelected.ClientID%>').value.replace(studId, '');
            }

        }

-------------------------------------------ASPX---------------------------------------------
 <ItemTemplate>


                            <asp:CheckBox ID="selectchk" onclick='<%# "AddRemoveSelected(this," + Eval("StudID") + ");" %>'
                                runat="server" />

                        </ItemTemplate>




-------------------------------------------------------ASPX.CS---------------------------

protected void Page_Load(object sender, EventArgs e)
    {
        ////Get hidden filed values
        string strRawIDs = hdnSelected.Value;

        string[] strIDs = strRawIDs.Split(',');

        ///////////////////////////

        

Alias

protected void Page_Load(object sender, EventArgs e)
    {
        if (ConnectionState.Closed == cn.State)
        {
            cn.Open();
        }

        //string strFName = "FirstName";
        //SqlDataAdapter da = new SqlDataAdapter("select * from student order by " + strFName, cn);

        SqlCommand cmd = new SqlCommand("Select * from student", cn);
        SqlDataReader dr = cmd.ExecuteReader();

        List<student> lstStudent = new List<student>();
        while (dr.Read())
        {
            student oStud = new student();
            oStud.StudentID = int.Parse(dr[0].ToString());
            oStud.FirstName = dr[1].ToString();
            oStud.LastName = dr[2].ToString();

            lstStudent.Add(oStud);
        }

        //string fname= "n.FirstName";
        var dt = (from n in lstStudent select new { StudID = n.StudentID, StudFirstName = n.FirstName, n.LastName, Roll = "" });
        //lstStudent.OrderBy(x =>  x.FirstName).ToList();

        //SqlDataAdapter da = new SqlDataAdapter("select * from student", cn);
        //DataTable dt = new DataTable();
        //da.Fill(dt);

        GridView1.DataSource = dt;
        GridView1.DataBind();

     
    }
}

Using Variable in Lambda expression

public partial class GridPage : System.Web.UI.Page
{

    SqlConnection cn = new SqlConnection("data source=SRIKANTA-PC\\SQLEXPRESS;initial catalog=adi;user id=sa;password=banka");

    protected void Page_Load(object sender, EventArgs e)
    {
     
        if(ConnectionState.Closed == cn.State)
        {
            cn.Open();
        }

 string fname= "n.FirstName";
        lstStudent = (from n in lstStudent orderby n.FirstName descending select n).ToList();


        //string strFName = "FirstName";
        //SqlDataAdapter da = new SqlDataAdapter("select * from student order by " + strFName, cn);

        SqlCommand cmd = new SqlCommand("Select * from student", cn);
        SqlDataReader dr = cmd.ExecuteReader();

        List<student> lstStudent = new List<student>();
        while (dr.Read())
        {
            student oStud = new student();
            oStud.StudentID = int.Parse(dr[0].ToString());
            oStud.FirstName = dr[1].ToString();
            oStud.LastName = dr[2].ToString();

            lstStudent.Add(oStud);
        }


        lstStudent = lstStudent.OrderBy(x =>  x.FirstName).ToList();

        //SqlDataAdapter da = new SqlDataAdapter("select * from student", cn);
        //DataTable dt = new DataTable();
        //da.Fill(dt);

        GridView1.DataSource = lstStudent;
        GridView1.DataBind();