Code Behind

using System;
using System.Collections;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.text.html.simpleparser;
using System.Configuration;
using System.Web;

public partial class aSelectEventExport : System.Web.UI.Page
{
    int RowCount;

    protected void Page_Load(object sender, EventArgs e)
    {
        int rigRedirect;

        if (Session["UserID"] == null)
        {
            Session.Abandon();
            Response.Redirect("EventLogin.aspx");
        }

        else
        {
            rigRedirect = (int)(Session["Rights"]);

            if (Session["UserID"] == null && rigRedirect != 6 && rigRedirect != 1)
            {
                Session.Abandon();
                Response.Redirect("EventLogin.aspx");
            }
            else if (rigRedirect != 6 && rigRedirect != 1)
            {
                Session.Abandon();
                Response.Redirect("EventLogin.aspx");
            }
            else
            {
                Label1.Text = "Welcome " + Session["Fname"] + " " + Session["Lname"];

            }
        }
    }

    public override void VerifyRenderingInServerForm(Control control)
    {
        /*Verifies that the control is rendered */
    }


    protected void SearchEvent_Click(object sender, EventArgs e)
    {

        SqlDataSource1.FilterExpression = "Event_Name LIKE '%" + txtSearchEvent.Text + "%' or Event_Desc LIKE '%" + txtSearchEvent.Text + "%'";

        GridView1.DataBind();
        RowCount = GridView1.Rows.Count;
        txtSearchEvent.Text = "";

    }

    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {
        int eventid;
        eventid = Convert.ToInt32(GridView1.SelectedDataKey.Value);

        String strCon = ConfigurationManager.ConnectionStrings["CME_RFID"].ConnectionString;
        DataTable dtExport = new DataTable();
        String strSQL = "SELECT PersonID, Person_Last, Person_First, Person_Title, Life_Number, Event_Name, EventID, CME_Event_Track_ID FROM CME_RFIDReader.vAttendanceList WHERE EventID = " + eventid;

        SqlConnection connect = new SqlConnection(strCon);
        SqlCommand command = new SqlCommand(strSQL, connect);

        SqlDataAdapter adExport = new SqlDataAdapter(command);

        adExport.Fill(dtExport);

     exportSpreadsheet(dtExport, "ExportReport");

    }


    public void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        ((TemplateField)GridView1.Columns[2]).EditItemTemplate = null;
        //GridView1.DataBind();
        Session["SelecetedRowIndex"] = e.NewEditIndex;
    }


    public static void exportSpreadsheet(DataTable dtTable, String strName)
    {
        HttpContext context = HttpContext.Current;
        context.Response.Clear();


        foreach (DataColumn column in dtTable.Columns)
        {
            context.Response.Write(column.ColumnName + ",");
        }
        context.Response.Write(Environment.NewLine);
        foreach (DataRow drRow in dtTable.Rows)
        {
            for (int i = 0; i < dtTable.Columns.Count; i++)
            {
                context.Response.Write(drRow[i].ToString().Replace(",", string.Empty) + ",");
            }
            context.Response.Write(Environment.NewLine);
        }
        context.Response.ContentType = "text/csv";
        context.Response.AppendHeader("Content-Disposition", "attachment; filename=" + strName + ".csv");
        context.Response.End();
    }

    protected void btnLogOff_Click(object sender, EventArgs e)
    {
        Session.Abandon();
        Session.RemoveAll();
        Response.Redirect("~/EventLogin.aspx");
    }

    protected void btnMenu_Click(object sender, EventArgs e)
    {
        Response.Redirect("~/EventSysMenu.aspx");
    }

    protected void bShowAll_Click(object sender, EventArgs e)
    {
        SqlDataSource1.FilterExpression = null;
    }
}