Date control with support for languages and different date formats

#region Namespaces
using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web;
using System.ComponentModel;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Web.UI.Design;
using System.Collections;
using System.Text;

using System.Globalization;
// resolve ambiguous reference
using AttributeCollection = System.ComponentModel.AttributeCollection;
#endregion

namespace i386.UI
{
	/// <summary>
	/// Drop down date control which support date formatting and different cultures.
	///  Author: Gavin Lyons, i386.com
	///  Version: 0.2 - 18 May 2005.
	///  
	///  --- You must leave this Summary section with the code.
	/// </summary>
	[DefaultProperty("Value")]
	public class DropDownDateTime: System.Web.UI.Control, INamingContainer, IPostBackDataHandler
	{
		private string _Culture;
		private bool _DebugMode=false;
		//MM/dd/yyyy for US dd/MM/yyyy for UK, this make the default setting automatic "		
		private string _DateFormat=System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat.ShortDatePattern;
		private string _MonthFormat = "MMMM";
		private bool _SelectCurrentDate = true;
		private bool _EnableSetDate=false;
		private bool _TimeInput=false;
		private int _YearsForward=0;
		private int  _YearsBack=0;
		

		/// <summary>
		/// Specifies a number of years from the current year. Value can also be negative
		/// </summary>
		[Bindable(true), 
		Description("Specifies how the month should be display MMM or MMMM"), 
		Category("Behavior"), 
		DefaultValue(null)]
		public string MonthFormat
		{
			get {return _MonthFormat;}
			set {_MonthFormat= value;}
		}


		public string Value 
		{
			get 
			{
				string s = (string)ViewState["Value"];
				if(s == null) return String.Empty;
				else return s;
			}				
			set 
			{
				this.SetSelected(value);
				ViewState["Value"] = value;
			}
		}

		/// <summary>
		/// Show the hidden box with the DateTime value, also display Culture and DateFormat. Useful for Debuging purposes.
		/// </summary>
		public bool DebugMode
		{
			get {return _DebugMode;}
			set {_DebugMode=value;}
		}
		/// <summary>
		/// Displays a TimeInput box - THIS FEATURE IS NOT WORKING YET!
		/// </summary>
		[Bindable(true), 
		Description("TimeInput"), 
		Category("Behavior"), 
		DefaultValue(false)]
		public bool TimeInput
		{
			get {return _TimeInput;}
			set {_TimeInput=value;}
		}
		/// <summary>
		/// Specifies a number of years from the current year. Value can also be negative
		/// </summary>
		[Bindable(true), 
		Description("Specifies a number of years from the current year. Value can also be negative"), 
		Category("Behavior"), 
		DefaultValue(0)]
		public int YearsBack
		{
			get {return _YearsBack;}
			set {_YearsBack = value;}
		}
		/// <summary>
		/// Specifies a number of years from the current year. Value can also be negative
		/// </summary>
		[Bindable(true), 
		Description("Specifies a number of years from the current year. Value can also be negative"), 
		Category("Behavior"), 
		DefaultValue(0)]
		public int YearsForward
		{
			get {return _YearsForward;}
			set {_YearsForward= value;}
		}
		/// <summary>
		/// Enables a checkbox to activate the date dropdownlists, if the checkbox is not set then the date is blank!!!
		/// </summary>
		[Bindable(true), 
		Description("Enables a checkbox to activate the date dropdownlists, if the checkbox is not set then the date is blank!!!"), 
		Category("Behavior"), 
		DefaultValue(false)]
		public bool EnableSetDate
		{
			get {return _EnableSetDate;}
			set {_EnableSetDate=value;}
		}

		/// <summary>
		/// Specifies the date format output dd/MM/yyyy MM-dd-yyyy etc.. 
		/// If this is not set then the server date format is taken.  
		/// Please note MMM ddd MMMM dddd are not valid!!
		/// </summary>
		[Bindable(true), 
		Description("Specifies the date format output dd/MM/yyyy MM-dd-yyyy etc.. If this is not set then the server date format is taken. Please note MMM ddd MMMM dddd are not valid!!"), 
		Category("Behavior"), 
		DefaultValue(-1)]
		public string DateFormat
		{
			get {return _DateFormat;}
			set {_DateFormat = value;}
		}
		/// <summary>
		/// Specifies the date language, example en-GB for english, fr-FR for french etc..
		/// If this is not set the server culture is taken.
		/// </summary>
		[Bindable(true), 
		Description("Specifies the date language, example en-GB for english, fr-FR for french etc.. If this is not set the server culture is taken."), 
		Category("Behavior"), 
		DefaultValue(-1)]
		public string Culture
		{
			get {return _Culture;}
			set {_Culture = value;}
		}
		public bool SelectCurrentDate
		{
			get {return _SelectCurrentDate;}
			set {_SelectCurrentDate=value;}	
		}
		#region ViewState Properties
		private int SelectedDay
		{
			get
			{
				if(ViewState["SelectedDay"] == null)
					return -1;
				else
					return (int)ViewState["SelectedDay"];
			}
			set
			{
				ViewState["SelectedDay"] = value;
			}
		}

		private int SelectedMonth
		{
			get
			{
				if(ViewState["SelectedMonth"] == null)
					return -1;
				else
					return (int)ViewState["SelectedMonth"];
			}
			set
			{
				ViewState["SelectedMonth"] = value;
			}
		}

		private int SelectedYear
		{
			get
			{
				if(ViewState["SelectedYear"] == null)
					return -1;
				else
					return (int)ViewState["SelectedYear"];
			}
			set
			{
				ViewState["SelectedYear"] = value;
			}
		}
		private string SelectedTime
		{
			get
			{
				return (string)ViewState["SelectedTime"];
			}
			set
			{
				ViewState["SelectedTime"] = value;
			}
		}
		
		private bool Checked
		{
			get 
			{
				if(ViewState["Checked"] == null)
					return false;
				else
					return (bool)ViewState["SelectedYear"];
			}
			set
			{
				ViewState["Checked"] = value;
			}
		}
		#endregion
		private static readonly object EventControlChanged = new object();
		public event EventHandler Change;
		public DropDownDateTime()
		{
			this.Load +=new EventHandler(DropDownDateTime_Load);
			this.Init +=new EventHandler(DropDownDateTime_Init);
		}
		private void DropDownDateTime_Init(object sender, EventArgs e)
		{
			if(Page != null)
			{
				// Register the control with the page's postback mechanism, or
				// the control will not update on Postback
				Page.RegisterRequiresPostBack(this);
			}
			//			if(this.DetermineRenderUplevel() && this.EnableClientScript)
			// Use the EnableClientScript property to specify whether client-side validation is enabled.
			// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemWebUIWebControlsBaseValidatorClassEnableClientScriptTopic.asp
			// The DetermineRenderUplevel method is a helper function used primarily by the RenderUplevel property to determine whether the client's browser supports uplevel rendering. For a browser to support uplevel rendering, it must support Internet Explorer Document Object Model (DOM) version 4 or later and ECMAScript version 1.2 or later.
			// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemwebuiwebcontrolsbasevalidatorclassdeterminerenderupleveltopic.asp

			if (!Page.IsClientScriptBlockRegistered("DropDownDateTimeScript"))
			{
				// Might be an idea to put the Javascript Functions in the aspnet_client directory, so browsers could cache the JS functions.
				// interesting URL http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnvs05/html/webresource.asp
				#region Main Javascript Function
				string JSCode= @"
// Author Gavin Lyons, i386.com
//function for returning how many days there are in a month including leap years	
function DaysInMonth(WhichMonth, WhichYear)
{	
  var DaysInMonth = 31;
  if (WhichMonth == 4 || WhichMonth == 6 || WhichMonth == 9 || WhichMonth == 11) DaysInMonth = 30;
  if (WhichMonth == 2 && (WhichYear/4) != Math.floor(WhichYear/4))	DaysInMonth = 28;
  if (WhichMonth == 2 && (WhichYear/4) == Math.floor(WhichYear/4))	DaysInMonth = 29;
  return DaysInMonth;
}
//function to change the available days in a months
function ChangeOptionDays(Which, DateFormat)
{
	if (document.getElementById) { 
		DaysObject = document.getElementById(Which + '_Day');
		MonthObject = document.getElementById(Which + '_Month');
		YearObject = document.getElementById(Which + '_Year');
		TimeObject = document.getElementById(Which + '_Time');
		CheckBoxObject= document.getElementById(Which + '_CheckBox');
		DateBoxObject = document.getElementById(Which);
	} 
	else if (document.layers) { 
		DaysObject = document.layers[Which + '_Day'];
		MonthObject = document.layers[Which + '_Month'];
		YearObject = document.layers[Which + '_Year'];
		TimeObject = document.layers[Which + '_Time'];
		CheckBoxObject= document.layers[Which + '_CheckBox'];
		DateBoxObject = document.layers[Which]; 
	} 
	else if (document.all) { 
		DaysObject = document.all[Which + '_Day'];
		MonthObject = document.all[Which + '_Month'];
		YearObject = document.all[Which + '_Year'];
		TimeObject = document.all[Which + '_Time'];
		CheckBoxObject= document.all[Which + '_CheckBox'];
		DateBoxObject = document.all[Which];
	} 
	Day= DaysObject[DaysObject.selectedIndex].text;
	Month = MonthObject[MonthObject.selectedIndex].value;
	Year = YearObject[YearObject.selectedIndex].text;
	DaysForThisSelection = DaysInMonth(Month, Year);
	CurrentDaysInSelection = DaysObject.length;
	if (Day!='--' && Year!='--' && Month!='--' ) {
	if (CurrentDaysInSelection > DaysForThisSelection)
	{
		for (i=0; i<(CurrentDaysInSelection-DaysForThisSelection); i++)
		{
			DaysObject.options[DaysObject.options.length - 1] = null;
		}
	}
	if (DaysForThisSelection > CurrentDaysInSelection)
	{
		for (i=0; i<(DaysForThisSelection-CurrentDaysInSelection); i++)
		{
			NewOption = new Option(DaysObject.options.length + 1);
			DaysObject.add(NewOption);
		}
	}
	if (DaysObject.selectedIndex < 0) DaysObject.selectedIndex == 0;
	DateBoxObject.value=formatDate(new Date(Year, (Month-1), Day), DateFormat);
	if (CheckBoxObject)
	{
		if (CheckBoxObject.checked)
		{
			DaysObject.disabled=false;MonthObject.disabled=false;YearObject.disabled=false;
		}
		else
		{
			DaysObject.disabled=true;MonthObject.disabled=true;YearObject.disabled=true;DateBoxObject.value='';
		}
	}
	} else {DateBoxObject.value=''}	
}

  
  // Date Convertion functions
  function formatDate(vDate, vFormat){ 
    var vDay              = addZero(vDate.getDate()); 
    var vMonth            = addZero(vDate.getMonth()+1); 
    var vYearLong         = addZero(vDate.getFullYear()); 
    var vYearShort        = addZero(vDate.getFullYear().toString().substring(3,4)); 
    var vYear             = (vFormat.indexOf('yyyy')>-1?vYearLong:vYearShort) 
    var vHour             = addZero(vDate.getHours()); 
    var vMinute           = addZero(vDate.getMinutes()); 
    var vSecond           = addZero(vDate.getSeconds()); 
    var vDateString       = vFormat.replace(/dd/g, vDay).replace(/MM/g, vMonth).replace(/y{1,4}/g, vYear) 
    vDateString           = vDateString.replace(/hh/g, vHour).replace(/mm/g, vMinute).replace(/ss/g, vSecond) 
    return vDateString 
  } 
  function addZero(vNumber){return ((vNumber < 10) ? '0' : '') + vNumber;} 
";
				#endregion
				Page.RegisterClientScriptBlock("PickListScript", "<script language=\"javascript\" type=\"text/javascript\">" + JSCode + "</script>");
			}

		}
		private void DropDownDateTime_Load(object sender, EventArgs e)
		{
			//Be sure child controls exist so they can be manipulated
			EnsureChildControls();
		}
		protected override void CreateChildControls()
		{
			DateTime dt = DateTime.Today;
			// Use CurrentDate if Value is empty and SelectCurrentDate is true.
			if (SelectCurrentDate && this.Value=="")
			{
				// Use Current Date
				SelectedDay  = dt.Day;
				SelectedMonth = dt.Month;
				SelectedYear = dt.Year;
				DateTimeFormatInfo formatInfo = new DateTimeFormatInfo();
				formatInfo.FullDateTimePattern = DateFormat;
				this.Value = dt.ToString(DateFormat,formatInfo);
			}

			// Days
			DropDownList ddlboxDay = new DropDownList();
			ddlboxDay.ID ="Day";
			ddlboxDay.Attributes.Add("onchange","ChangeOptionDays('" + this.ClientID +"','" + DateFormat + "');");
			for ( int nDay = 1; nDay<32; nDay++)	ddlboxDay.Items.Add(nDay.ToString());
			
			// So we can restore the Culture later
			CultureInfo ExistingCulture = System.Threading.Thread.CurrentThread.CurrentCulture; 
			// Culture - changes language of months	
			if (Culture!=null)	System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo(Culture);	
			// Months
			DropDownList ddlboxMonth = new DropDownList();
			ddlboxMonth.ID ="Month";
			ddlboxMonth.Attributes.Add("onchange","ChangeOptionDays('" + this.ClientID +"','" + DateFormat + "');");
			for ( int nMonth=1; nMonth<=12; nMonth++)
			{ 
				DateTime MonthDate = new DateTime(2000,nMonth,1);
				ddlboxMonth.Items.Add(new ListItem(MonthDate.ToString(this.MonthFormat),nMonth.ToString()));
			}



			// Years (Forward and Back properties)	
			DropDownList ddlboxYear = new DropDownList();
			ddlboxYear.ID ="Year";
			ddlboxYear.Attributes.Add("onchange","ChangeOptionDays('" + this.ClientID +"','" + DateFormat + "');");
			ddlboxYear.ID ="Year";
			
			if (YearsBack>=0)
			{
				for (int nYear = -YearsBack; nYear<=YearsForward; nYear++)
				{
					int ddlYear =dt.Year+nYear;
					ddlboxYear.Items.Add(ddlYear.ToString());
				}
			}
			else
			{
				for (int nYear = YearsForward; nYear<=-YearsBack; nYear++)
				{
					int ddlYear =dt.Year-nYear;
					ddlboxYear.Items.Add(ddlYear.ToString());
				}
			}

			// Select the DropDownList for the year
			if (SelectedYear>0)
			{
				if  (ddlboxYear.Items.FindByValue(SelectedYear.ToString())!=null) // See if the year is in the list.
				{
					ddlboxYear.Items.FindByValue(SelectedYear.ToString()).Selected = true;
				}
			}
			if (SelectedMonth>0)	ddlboxMonth.Items.FindByValue(SelectedMonth.ToString()).Selected = true;
			if (SelectedDay>0)		ddlboxDay.Items.FindByValue(SelectedDay.ToString()).Selected = true;

			// Add Child Control
			Controls.Add(ddlboxDay);
			Controls.Add(ddlboxMonth);
			Controls.Add(ddlboxYear);

			// Time - Not Fully test or implemented yet!
			if (TimeInput)
			{ 
				TextBox txtTime = new TextBox();
				txtTime.Width = 60;
				txtTime.Text = SelectedTime; // Set for ViewState Value.
				txtTime.Attributes.Add("Size","8"); // Firefox support
				txtTime.ID = "Time";
				txtTime.Attributes.Add("onchange","ChangeOptionDays('" + this.ClientID +"','" + DateFormat + "');");
				LiteralControl lc = new LiteralControl("&nbsp;");
				Controls.Add(lc);				
				Controls.Add(txtTime);
			}

			if (EnableSetDate)
			{	// Checkbox
				CheckBox chkDate = new CheckBox();
				chkDate.ID = "CheckBox";
				chkDate.Checked = Checked;		
				chkDate.Attributes.Add("onclick","ChangeOptionDays('" + this.ClientID +"','" + DateFormat + "');");
				Controls.Add(chkDate);
				if (!Checked)
				{
					ddlboxYear.Enabled=false;
					ddlboxMonth.Enabled=false;
					ddlboxDay.Enabled=false;
					//this.Value="";
				}
				else
				{
					ddlboxYear.Enabled=true;
					ddlboxMonth.Enabled=true;
					ddlboxDay.Enabled=true;
				}
			}
			// Restore 
			System.Threading.Thread.CurrentThread.CurrentCulture = ExistingCulture;
		}

		protected virtual void OnChanged(EventArgs e)
		{
			EventHandler ControlChanged = (EventHandler)Events[EventControlChanged];
			if(ControlChanged != null)
				ControlChanged(this, e);
		}
		public event EventHandler Changed
		{
			add
			{
				Events.AddHandler(EventControlChanged, value);
			}
			remove
			{
				Events.RemoveHandler(EventControlChanged, value);
			}
		}
		protected virtual void OnChange(EventArgs e)
		{
			if (Change != null)
				// Raise event.
				Change(this, e);
		}
		protected override void OnPreRender(EventArgs e)
		{
			base.OnPreRender(e);
			if (Page != null)
			{
			}
		}
		protected override void Render(HtmlTextWriter output)
		{
			if (DebugMode)
			{
				DateTimeFormatInfo formatInfo = new DateTimeFormatInfo();
				output.Write("<input type=\"text\" name=\"" + this.ClientID + "\" id=\"" + this.ClientID + "\"  value=\"" + this.Value + "\"><br/>" + DateFormat + " "
					+ System.Threading.Thread.CurrentThread.CurrentCulture.DisplayName + "<br/>" + 
					Value + " MM " + SelectedMonth + " dd " + SelectedDay + " yyyy "  + SelectedYear + " time " + SelectedTime + "<br/>");
			}
			else
			{
				output.Write("<input type=\"hidden\" name=\"" + this.ClientID + "\" id=\"" + this.ClientID + "\"  value=\"" + this.Value + "\">");
			}
			EnsureChildControls();
			base.Render(output);
		}
		// Override RaisePostDataChangedEvent method.
		void IPostBackDataHandler.RaisePostDataChangedEvent()
		{
			// Call the event method. This is optional.
			OnChange(EventArgs.Empty);
		}
		bool IPostBackDataHandler.LoadPostData(string postDataKey, 
			System.Collections.Specialized.NameValueCollection postCollection)
		{
			int Day = 0;
			int Month = 0;
			int Year = 0;
			string Time = "";
			bool Changed = false;
			// Updates the Day Viewstate value
			if(postCollection[this.UniqueID.ToString() + ":Day"] != "")
			{
				Day = Int32.Parse(postCollection[this.UniqueID.ToString() + ":Day"]);
				if (Day != this.SelectedDay)
				{
					this.SelectedDay = Day;
					Changed = true;
				}
			}
			else
			{ // Probably don't need this bit
				if(this.SelectedDay != -1)
				{
					this.SelectedDay = -1;
					Changed = true;
				}
			}
			// Updates the Month Viewstate value
			if(postCollection[this.UniqueID.ToString() + ":Month"] != "")
			{
				Month = Int32.Parse(postCollection[this.UniqueID.ToString() + ":Month"]);
				if (Month != this.SelectedMonth)
				{
					this.SelectedMonth = Month;
					Changed = true;
				}
			}
			else
			{ // Probably don't need this bit
				if(this.SelectedMonth != -1)
				{
					this.SelectedMonth = -1;
					Changed = true;
				}
			}
			// Updates the Year Viewstate value 
			if(postCollection[this.UniqueID.ToString() + ":Year"] != "")
			{
				Year = Int32.Parse(postCollection[this.UniqueID.ToString() + ":Year"]);
				if (Year != this.SelectedYear)
				{
					this.SelectedYear = Year;
					Changed = true;
				}
			}
			else
			{
				if(this.SelectedYear != -1)
				{
					this.SelectedYear = -1;
					Changed = true;
				}
			}
			// Updates the Time Viewstate value  *** Implemented yet!
			if(postCollection[this.UniqueID.ToString() + ":Time"] != "")
			{
				Time = postCollection[this.UniqueID.ToString() + ":Time"];
				if (Time  != this.SelectedTime )
				{
					this.SelectedTime  = Time ;
					Changed = true;
				}
			}

			// Checkbox
			/*
			if(postCollection[this.UniqueID.ToString() + ":Checkbox"] != "")
			{
				Year = bool.Parse(postCollection[this.UniqueID.ToString() + ":Year"]);
				if (Year != this.SelectedYear)
				{
					this.SelectedYear = Year;
					Changed = true;
				}
			}
			*/
			if(this.SelectedDay == -1 && this.SelectedMonth == -1 && this.SelectedYear == -1)
				this.Value = "";
			else
			{
				// Build a DateTime string based on the DateFormat
				DateTimeFormatInfo formatInfo = new DateTimeFormatInfo();
				formatInfo.FullDateTimePattern = DateFormat;
				DateTime dt = new DateTime(this.SelectedYear, this.SelectedMonth, this.SelectedDay);
				this.Value = dt.ToString(DateFormat,formatInfo);
			}
			return Changed;
		}

		private void SetSelected(string StoredValue)
		{
			DateTimeFormatInfo formatInfo = new DateTimeFormatInfo();
			formatInfo.FullDateTimePattern = DateFormat;
			DateTime dt = DateTime.ParseExact(StoredValue,DateFormat,formatInfo);	
			SelectedDay  = dt.Day;
			SelectedMonth = dt.Month;
			SelectedYear = dt.Year;	
		}
	}
}