Implementing Model-View-Presenter in ASP.NET

using System;
using System.ComponentModel;
using System.Globalization;
using System.Reflection;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace SubSonic
{
	/// <summary>
	/// Summary description for CalendarControl.
	/// </summary>
	public class CalendarControl : TextBox
	{
		private const string DEFAULT_INVALID_DATE = "Please enter a valid date.";

		private const string DEFAULT_FORMAT = "MM/dd/yyyy";
		private const string DEFAULT_JAVASCRIPT_FORMAT = "%m/%d/%Y";
		private const string DEFAULT_LANGUAGE = "en";
		private Image imgCalendar;
		private DateTime? selectedDate;
		private string displayFormat;
		private string javaScriptFormat;
		private string language;
		private bool showTime = true;

        public CalendarControl()
		{
			//DisplayFormat = DEFAULT_FORMAT;
			//JavaScriptFormat = DEFAULT_JAVASCRIPT_FORMAT;
			//Language = DEFAULT_LANGUAGE;
            DisplayFormat = CultureInfo.CurrentCulture.DateTimeFormat.ShortDatePattern;
            if (!String.IsNullOrEmpty(DisplayFormat))
            {
                char splitter = CultureInfo.CurrentCulture.DateTimeFormat.DateSeparator[0];
                string[] format = DisplayFormat.Split(new char[] {splitter});
                StringBuilder sbFormat = new StringBuilder();
                for(int i = 0; i<format.Length; i++)
                {
                    sbFormat.Append("%");
                    sbFormat.Append(format[i][0]);
                    if(i + 1 != format.Length)
                    {
                        sbFormat.Append(splitter);
                    }
                }
                JavaScriptFormat = sbFormat.ToString().ToLower();
            }
            else
            {
                DisplayFormat = DEFAULT_FORMAT;
                JavaScriptFormat = DEFAULT_JAVASCRIPT_FORMAT;
            }
            Language = CultureInfo.CurrentCulture.TwoLetterISOLanguageName;
		}

		private Image CalendarImage
		{
			get
			{
				if (imgCalendar == null)
				{
					imgCalendar = new Image();

					imgCalendar.ID = "imgCalendar" + ClientID;
					imgCalendar.ImageAlign = ImageAlign.AbsMiddle;
				    imgCalendar.ImageUrl = Page.ClientScript.GetWebResourceUrl(GetType(), "SubSonic.Controls.Calendar.skin.calendar.gif");
                        //StylePath + "calendar.gif";
					imgCalendar.Style.Add("margin-left", "5px");
				}
				return imgCalendar;
			}
		} 

		[DefaultValue(DEFAULT_FORMAT)]
		public string DisplayFormat
		{
			get { return displayFormat; }
			set { displayFormat = value; }
		} 
        
		[DefaultValue(DEFAULT_JAVASCRIPT_FORMAT)]
		public string JavaScriptFormat
		{
			get { return javaScriptFormat; }
			set { javaScriptFormat = value; }
		}

        [DefaultValue(DEFAULT_LANGUAGE)]
        public string Language
        {
            get { return language; }
            set { language = value; }
        }

        public bool ShowTime
		{
			get { return showTime; }
			set { showTime = value; }
		}

        public DateTime? SelectedDate
        {
            get
            {
                string selDate = Text.Trim();
                if (!String.IsNullOrEmpty(selDate))
                {
                    selectedDate = DateTime.Parse(selDate);
                }
                else
                {
                    selectedDate = null;
                }
                return selectedDate;
            }
            set
            {
                selectedDate = value;
                if (selectedDate.HasValue)
                {
                    DateTime dt = selectedDate.Value;
                    Text = dt.ToString(DisplayFormat);
                }
                else
                {
                    Text = String.Empty;
                }
            }
        } 

        protected override void OnPreRender(EventArgs e)
        {
            string csslink = "<link href='" + Page.ClientScript.GetWebResourceUrl(GetType(), "SubSonic.Controls.Calendar.skin.theme.css") + "' rel='stylesheet' type='text/css' />";
            Page.Header.Controls.Add(new LiteralControl(csslink));
            Page.ClientScript.RegisterClientScriptInclude("CalendarMain", Page.ClientScript.GetWebResourceUrl(GetType(), "SubSonic.Controls.Calendar.calendar.js"));
            Page.ClientScript.RegisterClientScriptInclude("CalendarSetup", Page.ClientScript.GetWebResourceUrl(GetType(), "SubSonic.Controls.Calendar.calendar-setup.js"));

            const string langPrefix = "SubSonic.Controls.Calendar.lang.calendar-";
            
            

            if(String.IsNullOrEmpty(Language))
            {
                Language = DEFAULT_LANGUAGE;
            }

            if (Assembly.GetExecutingAssembly().GetManifestResourceStream(langPrefix + Language + ".js") == null)
            {
                Page.ClientScript.RegisterClientScriptInclude("CalendarLanguage", Page.ClientScript.GetWebResourceUrl(GetType(), langPrefix + DEFAULT_LANGUAGE + ".js"));
            }
            else
            {
                Page.ClientScript.RegisterClientScriptInclude("CalendarLanguage", Page.ClientScript.GetWebResourceUrl(GetType(), langPrefix + Language + ".js"));
            }
            base.OnPreRender(e);
        }

	    protected override void Render(HtmlTextWriter writer)
		{
			if (SelectedDate == DateTime.MinValue)
			{
				SelectedDate = DateTime.Now;
			}

			writer.WriteLine("<table cellpadding=\"0\" cellspacing=\"0\" border=\"0\">");
			writer.WriteLine("<tr>");
			writer.WriteLine("<td>");

			base.Render (writer);

			writer.WriteLine("</td><td>");

			CalendarImage.RenderControl(writer);  // render CalendarButton object

			writer.WriteLine("</td>");
			writer.WriteLine("</tr>");
			writer.WriteLine("</table>");

			Page.ClientScript.RegisterStartupScript(typeof(Page), "Calendar" + ClientID,
				"<script type=\"text/javascript\">" +
					"Calendar.setup( { " +
						"inputField: \"" + ClientID + "\", " +
						"ifFormat: \"" + JavaScriptFormat + "\", " +
						"button: \"" + CalendarImage.ClientID + "\", " +
						"date: \"" + SelectedDate + "\", " +
						"showsTime: " + (ShowTime ? "true" : "false") + " " +
					"} );" +
				"</script>");
		}
	}
}