How to create editable calender in asp.net with database

ASPX PAGE

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<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"

    CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">

</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

    <asp:Calendar ID="Calendar1" runat="server" BackColor="White" 

    BorderColor="Black" DayNameFormat="Shortest" Font-Names="Times New Roman" 

    Font-Size="10pt" ForeColor="Black" Height="343px" NextPrevFormat="FullMonth" 

    ondayrender="Calendar1_DayRender" 

    onselectionchanged="Calendar1_SelectionChanged" 

    onvisiblemonthchanged="Calendar1_VisibleMonthChanged" TitleFormat="Month" 

    Width="888px">

        <DayHeaderStyle BackColor="#CCCCCC" Font-Bold="True" Font-Size="7pt" 

            ForeColor="#333333" Height="10pt" />

        <DayStyle Width="14%" />

        <NextPrevStyle Font-Size="8pt" ForeColor="White" />

        <OtherMonthDayStyle ForeColor="#999999" />

        <SelectedDayStyle BackColor="#CC3333" ForeColor="White" />

        <SelectorStyle BackColor="#CCCCCC" Font-Bold="True" Font-Names="Verdana" 

            Font-Size="8pt" ForeColor="#333333" Width="1%" />

        <TitleStyle BackColor="Black" Font-Bold="True" Font-Size="13pt" 

            ForeColor="White" Height="14pt" />

        <TodayDayStyle BackColor="#CCCC99" />

</asp:Calendar>

</asp:Content>

CS PAGE

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using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

namespace WebApplication1

{

    public partial class _Default : System.Web.UI.Page

    {

        protected DataSet dsHolidays;

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                Calendar1.VisibleDate = DateTime.Today;

                FillHolidayDataset();

            }

        }

        protected void FillHolidayDataset()

        {

            DateTime firstDate = new DateTime(Calendar1.VisibleDate.Year,

                Calendar1.VisibleDate.Month, 1);

            DateTime lastDate = GetFirstDayOfNextMonth();

            dsHolidays = GetCurrentMonthData(firstDate, lastDate);

        }

        protected DateTime GetFirstDayOfNextMonth()

        {

            int monthNumber, yearNumber;

            if (Calendar1.VisibleDate.Month == 12)

            {

                monthNumber = 1;

                yearNumber = Calendar1.VisibleDate.Year + 1;

            }

            else

            {

                monthNumber = Calendar1.VisibleDate.Month + 1;

                yearNumber = Calendar1.VisibleDate.Year;

            }

            DateTime lastDate = new DateTime(yearNumber, monthNumber, 1);

            return lastDate;

        }

        protected DataSet GetCurrentMonthData(DateTime firstDate,

             DateTime lastDate)

{

    DataSet dsMonth = new DataSet();

    ConnectionStringSettings cs;

    cs = ConfigurationManager.ConnectionStrings["ConnectionString1"];

    String connString = cs.ConnectionString;

    SqlConnection dbConnection = new SqlConnection(connString);

    String query;

    query = "SELECT HolidayDate,Text FROM Holidays " + " WHERE HolidayDate >= @firstDate AND HolidayDate < @lastDate";

    SqlCommand dbCommand = new SqlCommand(query, dbConnection);

    dbCommand.Parameters.Add(new SqlParameter("@firstDate", 

        firstDate));

    dbCommand.Parameters.Add(new SqlParameter("@lastDate", lastDate));

    SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(dbCommand);

    try

    {

        sqlDataAdapter.Fill(dsMonth);

    }

    catch {}

    return dsMonth;

}

        protected void Calendar1_SelectionChanged(object sender, EventArgs e)

        {

        }

        protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)

        {

            DateTime nextDate;

            if (dsHolidays != null)

            {

                foreach (DataRow dr in dsHolidays.Tables[0].Rows)

                {

                    nextDate = (DateTime)dr["HolidayDate"];

                    if (nextDate == e.Day.Date)

                    {

                        e.Cell.BackColor = System.Drawing.Color.Yellow;

                        e.Cell.Text = nextDate.Day + "<br/> " + dr["Text"].ToString();

                        

                        

                    }

                }

            }

        }

        protected void Calendar1_VisibleMonthChanged(object sender, MonthChangedEventArgs e)

        {

            FillHolidayDataset();

        }

    }

}

Firstly created database in sql
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CREATE TABLE [dbo].[Holidays](
[id] [bigint] IDENTITY(1,1) NOT NULL,
[HolidayDate] [datetime] NULL,
[Text] [nvarchar](max) NULL
)