วิธีจัดการ event ใน calendar เมื่อคลิ้กไปยังวันที่

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Security;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Drawing;

namespace Project
{
    public partial class testCalendar : System.Web.UI.Page
    {
        clsDatabase clsDB = new clsDatabase();
        SqlConnection mycn;
        SqlDataAdapter myda;
        DataSet ds = new DataSet();
        DataSet dsSelDate;
        String strConn;
        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            strConn = "Data Source=localhost;uid=sa;pwd=1234;Initial Catalog=northwind";
            mycn = new SqlConnection(strConn);
            myda = new SqlDataAdapter("Select * FROM Calendar_Event", mycn);
            //myda.Fill(ds, "Table");

            GridView1.Visible = false;
            Calendar1.TodayDayStyle.BackColor = Color.Gray; //สี background ของวันนี้
            Calendar1.TodayDayStyle.ForeColor = Color.White; //สี ตัวหนังสือ ของวันนี้
        }
        protected void CalendarDRender(object sender, System.Web.UI.WebControls.DayRenderEventArgs e)
        {
            // If the month is CurrentMonth
            if (!e.Day.IsOtherMonth)
            {
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    if ((dr["DueDate"].ToString() != DBNull.Value.ToString()))
                    {
                        DateTime dtEvent = (DateTime)dr["DueDate"];
                        if (dtEvent.Equals(e.Day.Date))
                        {
                            e.Cell.BackColor = Color.PaleVioletRed;
                        }
                    }
                }
            }
            //If the month is not CurrentMonth then hide the Dates
            else
            {
                e.Cell.Text = "";
            }
        }

        protected void Calendar1_SelectionChanged1(object sender, EventArgs e)
        {
            //ดึง format เวลาจาก calendar
            System.Globalization.CultureInfo en = new System.Globalization.CultureInfo("en-US");
            String Date_clik = Calendar1.SelectedDate.ToString("MM/dd/yyyy", en);
            this.Literal1.Text = Date_clik;
            Literal1.Visible = true;


            myda = new SqlDataAdapter("Select * from Calendar_Event where DueDate='" + Calendar1.SelectedDate.ToString("MM/dd/yyyy", en) + "'", mycn);
            dsSelDate = new DataSet();
            //myda.Fill(dsSelDate, "AllTables");
            /*
            if (dsSelDate.Tables[0].Rows.Count == 0)
            {

                GridView1.Visible = false;
            }
           else*/
            {
               
                
                GridView1.Visible = true;
                GridView1.DataSource = dsSelDate;
                GridView1.DataBind();
                // DataGrid1.DataSource = dsSelDate;
                // DataGrid1.DataBind();
            }
        }



    }
}