mono/mcs/class/System.Web/System.Web.UI.WebControls/Calendar.cs

/**
 * Namespace: System.Web.UI.WebControls
 * Class:     Calendar
 *
 * Author:  Gaurav Vaish
 * Maintainer: [email protected]
 * Contact: <[email protected]>, <[email protected]>
 * Implementation: yes
 * Status:  98%
 *
 * (C) Gaurav Vaish (2001)
 */

using System;
using System.IO;
using System.Collections;
using System.Globalization;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Drawing;

namespace System.Web.UI.WebControls
{
	public class Calendar : WebControl, IPostBackEventHandler
	{
		//

		private TableItemStyle          dayHeaderStyle;
		private TableItemStyle          dayStyle;
		private TableItemStyle          nextPrevStyle;
		private TableItemStyle          otherMonthDayStyle;
		private SelectedDatesCollection selectedDates;
		private ArrayList               selectedDatesList;
		private TableItemStyle          selectedDayStyle;
		private TableItemStyle          selectorStyle;
		private TableItemStyle          titleStyle;
		private TableItemStyle          todayDayStyle;
		private TableItemStyle          weekendDayStyle;

		private static readonly object DayRenderEvent           = new object();
		private static readonly object SelectionChangedEvent    = new object();
		private static readonly object VisibleMonthChangedEvent = new object();

		private Color defaultTextColor;
		private System.Globalization.Calendar globCal;

		private static int MASK_WEEKEND  = (0x01 << 0);
		private static int MASK_OMONTH   = (0x01 << 1);
		private static int MASK_TODAY    = (0x01 << 2);
		private static int MASK_SELECTED = (0x01 << 3);
		private static int MASK_DAY      = (0x01 << 4);
		private static int MASK_UNIQUE = MASK_WEEKEND | MASK_OMONTH | MASK_TODAY | MASK_SELECTED;

		public Calendar(): base()
		{
			//TODO: Initialization
		}

		public int CellPadding
		{
			get
			{
				object o = ViewState["CellPadding"];
				if(o!=null)
					return (int)o;
				return 2;
			}
			set
			{
				ViewState["CellPadding"] = value;
			}
		}

		public int CellSpacing
		{
			get
			{
				object o = ViewState["CellSpacing"];
				if(o!=null)
					return (int)o;
				return 0;
			}
			set
			{
				if(value<-1)
					throw new ArgumentOutOfRangeException();
				ViewState["CellSpacing"] = value;
			}
		}

		public TableItemStyle DayHeaderStyle
		{
			get
			{
				if(dayHeaderStyle==null)
					dayHeaderStyle = new TableItemStyle();
				if(IsTrackingViewState)
					dayHeaderStyle.TrackViewState();
				return dayHeaderStyle;
			}
		}

		public DayNameFormat DayNameFormat
		{
			get
			{
				object o = ViewState["DayNameFormat"];
				if(o!=null)
					return (DayNameFormat)o;
				return DayNameFormat.Short;
			}
			set
			{
				if(!System.Enum.IsDefined(typeof(DayNameFormat),value))
					throw new ArgumentException();
				ViewState["DayNameFormat"] = value;
			}
		}

		public TableItemStyle DayStyle
		{
			get
			{
				if(dayStyle==null)
					dayStyle = new TableItemStyle();
				if(IsTrackingViewState)
					dayStyle.TrackViewState();
				return dayStyle;
			}
		}

		public FirstDayOfWeek FirstDayOfWeek
		{
			get
			{
				object o = ViewState["FirstDayOfWeek"];
				if(o!=null)
					return (FirstDayOfWeek)o;
				return FirstDayOfWeek.Default;
			}
			set
			{
				if(!System.Enum.IsDefined(typeof(FirstDayOfWeek), value))
					throw new ArgumentException();
				ViewState["FirstDayOfWeek"] = value;
			}
		}

		public string NextMonthText
		{
			get
			{
				object o = ViewState["NextMonthText"];
				if(o!=null)
					return (string)o;
				return "&gt;";
			}
			set
			{
				ViewState["NextMonthText"] = value;
			}
		}

		public NextPrevFormat NextPrevFormat
		{
			get
			{
				object o = ViewState["NextPrevFormat"];
				if(o!=null)
					return (NextPrevFormat)o;
				return NextPrevFormat.CustomText;
			}
			set
			{
				if(!System.Enum.IsDefined(typeof(NextPrevFormat), value))
					throw new ArgumentException();
				ViewState["NextPrevFormat"] = value;
			}
		}

		public TableItemStyle NextPrevStyle
		{
			get
			{
				if(nextPrevStyle == null)
					nextPrevStyle = new TableItemStyle();
				if(IsTrackingViewState)
					nextPrevStyle.TrackViewState();
				return nextPrevStyle;
			}
		}

		public TableItemStyle OtherMonthDayStyle
		{
			get
			{
				if(otherMonthDayStyle == null)
					otherMonthDayStyle = new TableItemStyle();
				if(IsTrackingViewState)
					otherMonthDayStyle.TrackViewState();
				return otherMonthDayStyle;
			}
		}

		public string PrevMonthText
		{
			get
			{
				object o = ViewState["PrevMonthText"];
				if(o!=null)
					return (string)o;
				return "&lt;";
			}
			set
			{
				ViewState["PrevMonthText"] = value;
			}
		}

		public DateTime SelectedDate
		{
			get
			{
				if(SelectedDates.Count > 0)
				{
					return SelectedDates[0];
				}
				return DateTime.MinValue;
			}
			set
			{
				if(value == DateTime.MinValue)
				{
					SelectedDates.Clear();
				} else
				{
					SelectedDates.SelectRange(value, value);
				}
			}
		}

		public SelectedDatesCollection SelectedDates
		{
			get
			{
				if(selectedDates==null)
				{
					if(selectedDatesList == null)
						selectedDatesList = new ArrayList();
					selectedDates = new SelectedDatesCollection(selectedDatesList);
				}
				return selectedDates;
			}
		}

		public TableItemStyle SelectedDayStyle
		{
			get
			{
				if(selectedDayStyle==null)
					selectedDayStyle = new TableItemStyle();
				if(IsTrackingViewState)
					selectedDayDtyle.TrackViewState();
				return selectedDayStyle;
			}
		}

		public CalendarSelectionMode SelectionMode
		{
			get
			{
				object o = ViewState["SelectionMode"];
				if(o!=null)
					return (CalendarSelectionMode)o;
				return CalendarSelectionMode.Day;
			}
			set
			{
				if(!System.Enum.IsDefined(typeof(CalendarSelectionMode), value))
					throw new ArgumentException();
				ViewState["SelectionMode"] = value;
			}
		}

		public string SelectedMonthText
		{
			get
			{
				object o = ViewState["SelectedMonthText"];
				if(o!=null)
					return (string)o;
				return "&gt;&gt;";
			}
			set
			{
				ViewState["SelectedMonthText"] = value;
			}
		}

		public TableItemStyle SelectorStyle
		{
			get
			{
				if(selectorStyle==null)
					selectorStyle = new TableItemStyle();
				return selectorStyle;
			}
		}

		public string SelectWeekText
		{
			get
			{
				object o = ViewState["SelectWeekText"];
				if(o!=null)
					return (string)o;
				return "&gt;";
			}
			set
			{
				ViewState["SelectWeekText"] = value;
			}
		}

		public bool ShowDayHeader
		{
			get
			{
				object o = ViewState["ShowDayHeader"];
				if(o!=null)
					return (bool)o;
				return true;
			}
			set
			{
				ViewState["ShowDayHeader"] = value;
			}
		}

		public bool ShowGridLines
		{
			get
			{
				object o = ViewState["ShowGridLines"];
				if(o!=null)
					return (bool)o;
				return false;
			}
			set
			{
				ViewState["ShowGridLines"] = value;
			}
		}

		public bool ShowNextPrevMonth
		{
			get
			{
				object o = ViewState["ShowNextPrevMonth"];
				if(o!=null)
					return (bool)o;
				return true;
			}
			set
			{
				ViewState["ShowNextPrevMonth"] = value;
			}
		}

		public bool ShowTitle
		{
			get
			{
				object o = ViewState["ShowTitle"];
				if(o!=null)
					return (bool)o;
				return true;
			}
			set
			{
				ViewState["ShowTitle"] = value;
			}
		}

		public TitleFormat TitleFormat
		{
			get
			{
				object o = ViewState["TitleFormat"];
				if(o!=null)
					return (TitleFormat)o;
				return TitleFormat.MonthYear;
			}
			set
			{
				if(!System.Enum.IsDefined(typeof(TitleFormat), value))
					throw new ArgumentException();
				ViewState["TitleFormat"] = value;
			}
		}

		public TableItemStyle TitleStyle
		{
			get
			{
				if(titleStyle==null)
					titleStyle = new TableItemStyle();
				if(IsTrackingViewState)
					titleStyle.TrackViewState();
				return titleStyle;
			}
		}

		public TableItemStyle TodayDayStyle
		{
			get
			{
				if(todayDayStyle==null)
					todayDayStyle = new TableItemStyle();
				if(IsTrackingViewState)
					todayDayStyle.TrackViewState();
				return todayDayStyle;
			}
		}

		public DateTime TodaysDate
		{
			get
			{
				object o = ViewState["TodaysDate"];
				if(o!=null)
					return (DateTime)o;
				return DateTime.Today;
			}
			set
			{
				ViewState["TodaysDate"] = value;
			}
		}

		public DateTime VisibleDate
		{
			get
			{
				object o = ViewState["VisibleDate"];
				if(o!=null)
					return (DateTime)o;
				return DateTime.MinValue;
			}
			set
			{
				ViewState["VisibleDate"] = value;
			}
		}

		public TableItemStyle WeekendDayStyle
		{
			get
			{
				if(weekendDayStyle == null)
					weekendDayStyle = new TableItemStyle();
				if(IsTrackingViewState)
				{
					weekendDayStyle.TrackViewState();
				}
				return weekendDayStyle;
			}
		}

		public event DayRenderEventHandler DayRender
		{
			add
			{
				Events.AddHandler(DayRenderEvent, value);
			}
			remove
			{
				Events.RemoveHandler(DayRenderEvent, value);
			}
		}

		public event EventHandler SelectionChanged
		{
			add
			{
				Events.AddHandler(SelectionChangedEvent, value);
			}
			remove
			{
				Events.RemoveHandler(SelectionChangedEvent, value);
			}
		}

		public event MonthChangedEventHandler VisibleMonthChanged
		{
			add
			{
				Events.AddHandler(VisibleMonthChangedEvent, value);
			}
			remove
			{
				Events.RemoveHandler(VisibleMonthChangedEvent, value);
			}
		}

		protected virtual void OnDayRender(TableCell cell, CalendarDay day)
		{
			if(Events!=null)
			{
				DayRenderEventHandler dreh = (DayRenderEventHandler)(Events[DayRenderEvent]);
				if(dreh!=null)
					dreh(this, new DayRenderEventArgs(cell, day));
			}
		}

		protected virtual void OnSelectionChanged()
		{
			if(Events!=null)
			{
				EventHandler eh = (EventHandler)(Events[SelectionChangedEvent]);
				if(eh!=null)
					eh(this, new EventArgs());
			}
		}

		protected virtual void OnVisibleMonthChanged(DateTime newDate, DateTime prevDate)
		{
			if(Events!=null)
			{
				MonthChangedEventHandler mceh = (MonthChangedEventHandler)(Events[VisibleMonthChangedEvent]);
				if(mceh!=null)
					mceh(this, new MonthChangedEventArgs(newDate, prevDate));
			}
		}

		/// <remarks>
		/// See test6.aspx in Tests directory for verification
		/// </remarks>
		void IPostBackEventHandler.RaisePostBackEvent(string eventArgument)
		{
			globCal = DateTimeFormatInfo.CurrentInfo.Calendar;
			DateTime visDate = GetEffectiveVisibleDate();
			//FIXME: Should it be String.Compare(eventArgument, "nextMonth", false);
			if(eventArgument == "nextMonth")
			{
				VisibleDate = globCal.AddMonths(visDate, 1);
				OnVisibleDateChanged(VisibleDate, visDate);
				return;
			}
			if(eventArgument == "prevMonth")
			{
				VisibleDate = globCal.AddMonths(visDate, -1);
				OnVisibleDateChanged(VisibleDate, visDate);
				return;
			}
			if(eventArgument == "selectMonth")
			{
				DateTime oldDate = new DateTime(globCal.GetYear(visDate), globCal.GetMonth(visDate), 1, globCal);
				SelectRangeInternal(oldDate, globCal.AddDays(gloCal.AddMonths(oldDate, 1), -1), visDate);
				return;
			}
			if(String.Compare(eventArgument, 0, "selectWeek", 0, "selectWeek".Length)==0)
			{
				int week = -1;
				try
				{
					week = Int32.Parse(eventArgument.Substring("selectWeek".Length));
				} catch(Exception e)
				{
				}
				if(week >= 0 && week <= 5)
				{
					DateTime weekStart = globCal.AddDays(GetFirstCalendarDay(visDate), week * 7);
					SelectRangeInternal(weekStart, globCal.AddDays(weekStart, 6), visDate);
				}
				return;
			}
			if(String.Compare(eventArgument, 0, "selectDay", 0, "selectDay".Length)==0)
			{
				int day = -1;
				try
				{
					day = Int32.Parse(eventArgument.Substring("selectDay".Length);
				} catch(Exception e)
				{
				}
				if(day >= 0 && day <= 42)
				{
					DateTime dayStart = globCal.AddDays(GetFirstCalendarDay(visDate), day);
					SelectRangeInternal(dayStart, dayStart, visDate);
				}
			}
		}

		protected override void Render(HtmlTextWriter writer)
		{
			//TODO: Implement me
			globCal = DateTimeFormatInfo.CurrentInfo.Calendar;
			DateTime visDate   = GetEffectiveVisibleDate()
			DateTime firstDate = GetFirstCalendarDay(visDate);
			
			bool isEnabled = false;
			bool isHtmlTextWriter = false;
			if(Page == null || Site == null || Site.DesignMode == null )
			{
				isEnabled = false;
				isHtmlTextWriter = false;
			} else
			{
				isEnabled = Enabled;
				isHtmlTextWriter = (writer.GetType() != typeof(HtmlTextWriter));
			}
			defaultTextColor = ForeColor;
			if(defaultTextColor == Color.Empty)
				defaultTextColor = Color.Black;
			
			Table calTable = new Table();
			calTable.ID = ID;
			calTable.CopyBaseAttributes(this);
			if(ControlStyleCreated)
				ApplyStyle(ControlStyle);
			calTable.Width = Width;
			calTable.Height = Height;
			calTable.CellSpacing = CellSpacing;
			calTable.CellPadding = CellPadding;
			
			if(ControlStyleCreated && ControlStyle.IsSet(Style.BORDERWIDTH) && BorderWidth != Unit.Empty)
			{
				calTable.BorderWidth = BorderWidth;
			} else
			{
				calTable.BorderWidth = Unit.Pixel(1);
			}
			
			if(ShowGridLines)
				calTable.GridLines = GridLines.Both;
			else
				calTable.GridLines = GridLines.None;
			
			calTable.RenderBeginTag(writer);
			if(ShowTitle)
				RenderTitle(writer, visDate, SelectionMode, isEnabled);
			if(ShowDayHeader)
				RenderHeader(writer, firstDate, SelectionMode, isEnabled, isHtmlTextWriter);
			RenderAllDays(writer, firstDate, visDate, SelectionMode, isEnabled, isHtmlTextWriter);
			
			calTable.RenderEndTag(writer);
		}

		protected override ControlCollection CreateControlCollection()
		{
			return new EmptyControlCollection(this);
		}

		protected override void LoadViewState(object savedState)
		{
			if(savedState!=null)
			{
				if(ViewState["_CalendarSelectedDates"] != null)
					SelectedDates = (SelectedDatesCollection)ViewState["_CalendarSelectedDates"];

				object[] states = (object[]) savedState;
				if(states[0] != null)
					base.LoadViewState(states[0]);
				if(states[1] != null)
					DayHeaderStyle.LoadViewState(states[1]);
				if(states[2] != null)
					DayStyle.LoadViewState(states[2]);
				if(states[3] != null)
					NextPrevStyle.LoadViewState(states[3]);
				if(states[4] != null)
					OtherMonthStyle.LoadViewState(states[4]);
				if(states[5] != null)
					SelectedDayStyle.LoadViewState(states[5]);
				if(states[6] != null)
					SelectorStyle.LoadViewState(states[6]);
				if(states[7] != null)
					TitleStyle.LoadViewState(states[7]);
				if(states[8] != null)
					TodayDayStyle.LoadViewState(states[8]);
				if(states[9] != null)
					WeekendDayStyle.LoadViewState(states[9]);
			}
		}

		protected override object SaveViewState()
		{
			ViewState["_CalendarSelectedDates"] = (SelectedDates.Count > 0 ? selectedDates : null);
			object[] states = new object[11];
			states[0] = base.SaveViewState();
			states[1] = (dayHeaderStyle == null ? null : dayHeaderStyle.SaveViewStyle());
			states[2] = (dayStyle == null ? null : dayStyle.SaveViewStyle());
			states[3] = (nextPrevStyle == null ? null : nextPrevStyle.SaveViewStyle());
			states[4] = (otherMonthDayStyle == null ? null : otherMonthDayStyle.SaveViewStyle());
			states[5] = (selectedDayStyle == null ? null : selectedDayStyle.SaveViewStyle());
			states[6] = (selectorStyle == null ? null : selectorStyle.SaveViewStyle());
			states[7] = (titleStyle == null ? null : titleStyle.SaveViewStyle());
			states[8] = (todayDayStyle == null ? null : todayDayStyle.SaveViewStyle());
			states[9] = (weekendDayStyle == null ? null : weekendDayStyle.SaveViewStyle());
			for(int i=0; i < states.Length)
			{
				if(states[i]!=null)
					return states;
			}
			return null;
		}

		protected override void TrackViewState(): TrackViewState()
		{
			if(titleStyle!=null)
			{
				titleStyle.TrackViewState();
			}
			if(nextPrevStyle!=null)
			{
				nextPrevStyle.TrackViewState();
			}
			if(dayStyle!=null)
			{
				dayStyle.TrackViewState();
			}
			if(dayHeaderStyle!=null)
			{
				dayHeaderStyle.TrackViewState();
			}
			if(todayDayStyle!=null)
			{
				todayDayStyle.TrackViewState();
			}
			if(weekendDayStyle!=null)
			{
				weekendDayStyle.TrackViewState();
			}
			if(otherMonthDayStyle!=null)
			{
				otherMonthDayStyle.TrackViewState();
			}
			if(selectedDayStyle!=null)
			{
				selectedDayStyle.TrackViewState();
			}
			if(selectorStyle!=null)
			{
				selectorStyle.TrackViewState();
			}
		}

		[MonoTODO("Individual_Day_Rendering_Part_Left")]
		private void RenderAllDays(HtmlTextWriter writer, DateTime firstDay, DateTime activeDate, CalendarSelectionMode mode, bool isActive, bool isDownLevel)
		{
			TableCell weeksCell;
			string weeksCellData;
			bool isWeekMode = (mode == CalendarSelectionMode.DayWeek || mode == CalendarSelectionMode.DayWeekMonth);
			if(isWeekMode)
			{
				weeksCell = new TableCell();
				weeksCell.Width = Unit.Percentage(12);
				weeksCell.HorizontalAlign = HorizontalAlign.Center;
				weeksCell.ApplyStyle(SelectorStyle);
				if(!isDownLevel)
					weeksCellData = GetHtmlForCell(weeksCell, isActive);
			}
			bool dayRenderBool = false;
			if(GetType() != typeof(Calendar) || Events[DayRenderEvent] != null || !isDownLevel)
				dayRenderBool = true;

			string[] content = new string[0x01 << 4];
			int definedStyles = MASK_SELECTED;
			if(weekendStyle != null && !weekendStyle.IsEmpty)
				definedStyles |= MASK_WEEKEND;
			if(otherMonthStyle != null && !otherMonthStyle.IsEmpty)
				definedStyles |= MASK_OMONTH;
			if(todayDayStyle != null && todayDayStyle.IsEmpty)
				definedStyles |= MASK_TODAY;
			if(dayStyle != null && !dayStyle.IsEmpty)
				definedStyles |= MASK_DAY;

			bool selectDayBool = false;
			if(isActive && mode != CalendarSelectionMode.None)
			{
				selectDayBool = true;
			}
			
			for(int crr = 0; crr < 6; crr++)
			{
				writer.Write("<tr>");
				if(isWeekMode)
				{
					if(isDownLevel)
					{
						string cellText = GetCalendarLinkText("selectWeek" + crr.ToString(), SelectWeekText, isActive, weeksCell.ForeColor);
						weeksCell.Text = cellText;
						RenderCalendarCell(writer, weeksCell, cellText);
					} else
					{
						if(isActive)
						{
							writer.Write(String.Format(weeksCellData, "selectWeek" + crr.ToString(), SelectWeekText));
						} else
						{
							writer.Write(String.Format(weeksCellData, "selectWeek" + crr.ToString()));
						}
					}
				}
				for(int crc = 0; crc < 7; crc++)
				{
					// have to display for each day in the week.
					throw new NotImplementedException();
				}
			}

			throw new NotImplementedException();
		}
		
		private int GetMask(CalendarDay day)
		{
			int retVal = MASK_DAY;
			if(day.IsSelected)
				retVal |= MASK_SELECTED;
			if(day.IsToday)
				retVal |= MASK_TODAY;
			if(day.IsOtherMonth)
				retVal |= MASK_OMONTH;
			if(day.IsWeekend)
				retVal |= MASK_WEEKEND;
			return retVal;
		}

		/// <remarks>
		/// Refers to the second line of the calendar, that contains a link
		/// to select whole month, and weekdays as defined by DayNameFormat
		/// </remarks>
		private void RenderHeader(HtmlTextWriter writer, DateTime firstDay, CalendarSelectionMode mode, bool isActive, bool isDownLevel)
		{
			writer.Write("<tr>");
			bool isWeekMode = (mode == CalendarSelectionMode.DayWeek || mode == CalendarSelectionMode.DayWeekMonth);
			TableCell headerCell = new TableCell();
			headerCell.HorizontalAlign = HorizontalAlign.Center;
			string selMthText = String.Empty;
			if(isWeekMode)
			{
				headerCell.ApplyStyle(SelectorStyle);
				selMthText = GetCalendarLinkText("selectMonth", SelectMonthText, isActive, SelectorStyle.ForeColor);
			} else
			{
				headerCell.ApplyStyle(DayHeaderStyle);
			}
			RenderCalendarCell(writer, headerCell, selMthText);
			
			TableCell dayHeaderCell = new TableCell();
			dayHeaderCell.HorizontalAlign = HorizontalAlign.Center;
			string content = null;
			if(!isDownLevel)
			{
				content = GetHtmlForCell(dayHeaderCell, isActive);
			}
			int dayOfWeek = (int)globCal.GetDayOfWeek(firstDay);
			for(int currDay = dayOfWeek; currDay < dayOfWeek + 7; currDay++)
			{
				int effDay = (currDay % 7);
				string currDayContent = String.Empty;
				switch(DayNameFormat)
				{
					DayNameFormat.Full:            currDayContent = DateTimeFormatInfo.GetDayName(effDay);
					                               break;
					DayNameFormat.FirstLetter:     currDayContent = DateTimeFormatInfo.GetDayName(effDay).Substring(0,1);
					                               break;
					DayNameFormat.FirstTwoLetters: currDayContent = DateTimeFormatInfo.GetDayName(effDay).Substring(0,2);
					                               break;
					DayNameFormat.Short:
					default:                       currDayContent = DateTimeFormatInfo.GetAbbreviatedDayName(effDay);
					                               break;
				}
				if(isDownLevel)
				{
					RenderCalendarCell(writer, dayHeaderCell, currDayContent);
				} else
				{
					writer.Write(String.Format(content, currDayContent);
				}
			}
			writer.Write("</tr>");
		}

		private void RenderTitle(HtmlTextWriter writer, DateTime visibleDate, CalendarSelectionMode mode, bool isActive)
		{
			writer.Write("<tr>");
			Table innerTable = new Table();
			TableCell titleCell = new TableCell();
			bool isWeekMode = (mode == CalendarSelectionMode.DayWeek || mode == CalendarSelectionMode.DayWeekMonth);
			titleCell.ColumnSpan = (isWeekMode ? 8 : 7);
			titleCell.BackColor = "Silver";
			
			innerTable.GridLines = GridLine.None;
			innerTable.Width = Unit.Percentage(100);
			innerTable.CellSpacing = 0;
			ApplyTitleStyle(innerTable, titleCell, TitleStyle);
			
			innerTable.RenderBeginTag(writer);
			titleCell.RenderBeginTag(writer);
			
			writer.Write("<tr>");
			string prevContent = String.Empty;
			if(ShowNextPrevMonth)
			{
				TableCell prevCell = new TableCell();
				prevCell.Width = Unit.Percentage(15);
				prevCell.HorizontalAlign = HorizontalAlign.Left;
				if(NextPrevFormat == NextPrevFormat.CustomText)
				{
					prevContent = PrevMonthText;
				} else
				{
					int pMthInt = globCal.GetMonth(globCal.AddMonths(visibleDate, -1));
					if(NextPrevFormat == NextPrevFormat.FullText)
						prevContent = DateTimeFormatInfo.CurrentInfo.GetMonthName(pMthInt);
					else
						prevContent = DateTimeFormatInfo.CurrentInfo.GetAbbreviatedMonthName(pMthInt);
				}
				prevCell.ApplyStyle(NextPrevStyle);
				RenderCalendarCell(writer, prevCell, GetCalendarLinkText("prevMonth", prevContent, isActive, NextPrevStyle.ForeColor));
			}
			TableCell currCell = new TableCell();
			currCell.Width = Unit.Percentage(70);
			if(TitleStyle.HorizontalAlign == HorizontalAlign.NotSet)
				currCell.HorizontalAlign = HorizontalAlign.Center;
			else
				currCell.HorizontalAlign = TitleStyle.HorizontalAlign;
			currCell.Wrap = TitleStyle.Wrap;
			string currMonthContent = String.Empty;
			if(TitleFormat == TitleFormat.Month)
			{
				currMonthContent = visibleDate.ToString("MMMM");
			} else
			{
				string cmcFmt = DateTimeFormatInfo.CurrentInfo.YearMonthPattern;
				if(cmcFmt.IndexOf(',') >= 0)
				{
					cmcFmt = "MMMM yyyy";
				}
				currMonthContent = visibleDate.ToString(cmcFmt);
			}
			string nextContent = String.Empty;
			if(ShowNextPrevMonth)
			{
				TableCell nextCell = new TableCell();
				nextCell.Width = Unit.Percentage(15);
				nextCell.HorizontalAlign = HorizontalAlign.Left;
				if(NextPrevFormat == NextPrevFormat.CustomText)
				{
					nextContent = PrevMonthText;
				} else
				{
					int nMthInt = globCal.GetMonth(globCal.AddMonths(visibleDate, 1));
					if(NextPrevFormat == NextPrevFormat.FullText)
						nextContent = DateTimeFormatInfo.CurrentInfo.GetMonthName(nMthInt);
					else
						nextContent = DateTimeFormatInfo.CurrentInfo.GetAbbreviatedMonthName(nMthInt);
				}
				nextCell.ApplyStyle(NextPrevStyle);
				RenderCalendarCell(writer, nextCell, GetCalendarLinkText("nextMonth", nextContent, isActive, NextPrevStyle.ForeColor));
			}
			
			writer.Write("</tr>");
			titleCell.RenderEndTag(writer);
			innerTable.RenderEndTag(writer);
			
			writer.Write("</tr>");
		}

		private void ApplyTitleStyle(Table table, TableCell cell, TableItemStyle style)
		{
			if(style.BackColor != Color.Empty)
			{
				cell.BackColor = style.BackColor;
			}
			if(style.BorderStyle != BorderStyle.NotSet)
			{
				cell.BorderStyle = style.BorderStyle;
			}
			if(style.BorderColor != Color.Empty)
			{
				cell.BorderColor = style.BorderColor;
			}
			if(style.BorderWidth != Unit.Empty)
			{
				cell.BorderWidth = style.BorderWidth;
			}
			if(style.Height != Unit.Empty)
			{
				cell.Height = style.Height;
			}
			if(style.VerticalAlign != VerticalAlign.NotSet)
			{
				cell.VerticalAlign = style.VerticalAlign;
			}
			
			if(style.ForeColor != Color.Empty)
			{
				table.ForeColor = style.ForeColor;
			} else if(ForeColor != Color.Empty)
			{
				table.ForeColor = ForeColor;
			}
			
			table.Font.CopyFrom(style.Font);
			table.Font.MergeWith(Font);
		}

		private void RenderCalendarCell(HtmlTextWriter writer, TableCell cell, string text)
		{
			cell.RenderBeginTag(writer);
			writer.Write(text);
			cell.RenderEndTag(writer);
		}

		private DateTime GetFirstCalendarDay(DateTime visibleDate)
		{
			DayOfWeek firstDay = ( FirstDayOfWeek == FirstDayOfWeek.Default ? DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek : FirstDayOfWeek);
			//FIXME: is (int)(Enum) correct?
			int days = (int)globCal.GetDayOfWeek(visibleDate) - (int)firstDay;
			if(days < 0)
			{
				days += 7;
			}
			return globCal.AddDays(visibleDate, -days);
		}

		private DateTime GetEffectiveVisibleDate()
		{
			DateTime dt = VisibleDate;
			if(dt.Equals(DateTime.MinValue))
			{
				dt = TodaysDate;
			}
			return new DateTime(globCal.GetYear(dt), globCal.GetMonth(dt), globCal.GetDayOfMonth(dt), globCal);
		}

		/// <summary>
		/// Creates text to be displayed, with all attributes if to be
		/// shown as a hyperlink
		/// </summary>
		private string GetCalendarLinkText(string eventArg, string text, Color foreground, bool isLink)
		{
			if(isLink)
			{
				StringBuilder dispVal = new StringBuilder();
				dispVal.Append("<a href=\"");
				dispVal.Append(Page.GetPostBackClientHyperlink(this, eventArg));
				dispVal.Append("\" style=\"color: ");
				if(foreground.IsEmpty)
				{
					dispVal.Append(ColorTranslator.ToHtml(defaultTextColor));
				} else
				{
					dispVal.Append(ColorTranslator.ToHtml(foreground));
				}
				dispVal.Append("\">");
				dispVal.Append(text);
				dispVal.Append("</a>");
				return dispVal.ToString();
			}
			return text;
		}

		private string GetHtmlForCell(TableCell cell, bool showLinks)
		{
			StringWriter sw = new StringWriter();
			HtmlTextWriter htw = new HtmlTextWriter(sw);
			cell.RenderBeginTag(htw);
			if(showLinks)
			{
				htw.Write(GetCalendarLinkText("{0}", "{1}", cell.ForeColor, showLinks));
			} else
			{
				htw.Write("{0}");
			}
			cell.RenderEndTag(htw);
			return sw.ToString();
		}

		internal DateTime SelectRangeInternal(DateTime fromDate, DateTime toDate, DateTime visibleDate)
		{
			TimeSpan span = fromDate - toDate;
			if(SelectedDates.Count != span.Days || SelectedDates[SelectedDate.Count - 1]!= toDate)
			{
				SelectedDates.SelectRange(fromDate, toDate);
				OnSelectionChanged();
			}
			if(globCal.GetMonth(fromDate) == globCal.GetMonth(fromDate) && globCal.GetMonth(fromDate) != globCal.GetMonth(visibleDate)
			{
				VisibleDate = new DateTime(globCal.GetYear(fromDate), globCal.getMonth(fromDate), 1, globCal);
				OnVisibleMonthChanged(VisibleDate, visibleDate);
			}
		}
	}
}