ChtmlCalendarAdapter.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / MIT / System / Web / UI / MobileControls / Adapters / ChtmlCalendarAdapter.cs / 1305376 / ChtmlCalendarAdapter.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

using System; 
using System.Globalization; 
using System.IO;
using System.Text; 
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.MobileControls; 
using System.Web.UI.MobileControls.Adapters;
using System.Web.UI.WebControls; 
using System.Diagnostics; 
using System.Collections;
using System.Security.Permissions; 

#if COMPILING_FOR_SHIPPED_SOURCE
namespace System.Web.UI.MobileControls.ShippedAdapterSource
#else 
namespace System.Web.UI.MobileControls.Adapters
#endif 
 
{
    /* 
     * ChtmlCalendarAdapter provides the cHTML device functionality for Calendar
     * control.  It is using secondary UI support to provide internal screens
     * to allow the user to pick or enter a date.
     * 
     * Copyright (c) 2000 Microsoft Corporation
     */ 
    ///  
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [Obsolete("The System.Web.Mobile.dll assembly has been deprecated and should no longer be used. For information about how to develop ASP.NET mobile applications, see http://go.microsoft.com/fwlink/?LinkId=157231.")]
    public class ChtmlCalendarAdapter : HtmlControlAdapter
    {
        private SelectionList _selectList; 
        private TextBox _textBox;
        private Command _command; 
        private List _optionList; 
        private List _monthList;
        private List _weekList; 
        private List _dayList;
        private int _chooseOption = FirstPrompt;
        private int _monthsToDisplay;
        private int _eraCount = 0; 
        private bool _requireFormTag = false;
 
        ///////////////////////////////////////////////////////////////////// 
        // Globalization of Calendar Information:
        // Similar to the globalization support of the ASP.NET Calendar control, 
        // this support is done via COM+ thread culture info/object.
        // Specific example can be found from ASP.NET Calendar spec.
        /////////////////////////////////////////////////////////////////////
 
        // This member variable is set each time when calendar info needs to
        // be accessed and be shared for other helper functions. 
        private Globalization.Calendar _threadCalendar; 

        private String _textBoxErrorMessage; 

        // Since SecondaryUIMode is an int type, we use constant integers here
        // instead of enum so the mode can be compared without casting.
        private const int FirstPrompt = NotSecondaryUIInit; 
        private const int OptionPrompt = NotSecondaryUIInit + 1;
        private const int TypeDate = NotSecondaryUIInit + 2; 
        private const int DateOption = NotSecondaryUIInit + 3; 
        private const int WeekOption = NotSecondaryUIInit + 4;
        private const int MonthOption = NotSecondaryUIInit + 5; 
        private const int ChooseMonth = NotSecondaryUIInit + 6;
        private const int ChooseWeek = NotSecondaryUIInit + 7;
        private const int ChooseDay = NotSecondaryUIInit + 8;
        private const int DefaultDateDone = NotSecondaryUIInit + 9; 
        private const int TypeDateDone = NotSecondaryUIInit + 10;
        private const int Done = NotSecondaryUIInit + 11; 
 
        private const String DaySeparator = " - ";
        private const String Space = " "; 

        /// 
        protected new Calendar Control
        { 
            get
            { 
                return (Calendar)base.Control; 
            }
        } 

        /// 
        public override bool RequiresFormTag
        { 
            get
            { 
                return _requireFormTag; 
            }
        } 

        /// 
        public override void OnInit(EventArgs e)
        { 
            ListCommandEventHandler listCommandEventHandler;
 
            // Create secondary child controls for rendering secondary UI. 
            // Note that their ViewState is disabled because they are used
            // for rendering only. 
            //---------------------------------------------------------------

            _selectList = new SelectionList();
            _selectList.Visible = false; 
            _selectList.EnableViewState = false;
            Control.Controls.Add(_selectList); 
 
            _textBox = new TextBox();
            _textBox.Visible = false; 
            _textBox.EnableViewState = false;
            EventHandler eventHandler = new EventHandler(this.TextBoxEventHandler);
            _textBox.TextChanged += eventHandler;
            Control.Controls.Add(_textBox); 

            _command = new Command(); 
            _command.Visible = false; 
            _command.EnableViewState = false;
            Control.Controls.Add(_command); 

            // Below are initialization of several list controls.  A note is
            // that here the usage of DataMember is solely for remembering
            // how many items a particular list control is bounded to.  The 
            // property is not used as originally designed.
            //--------------------------------------------------------------- 
 
            _optionList = new List();
            _optionList.DataMember = "5"; 
            listCommandEventHandler = new ListCommandEventHandler(this.OptionListEventHandler);
            InitList(_optionList, listCommandEventHandler);

            // Use MobileCapabilities to check screen size and determine how 
            // many months should be displayed for different devices.
            _monthsToDisplay = MonthsToDisplay(Device.ScreenCharactersHeight); 
 
            // Create the list of months, including [Next] and [Prev] links
            _monthList = new List(); 
            _monthList.DataMember = Convert.ToString(_monthsToDisplay + 2, CultureInfo.InvariantCulture);
            listCommandEventHandler = new ListCommandEventHandler(this.MonthListEventHandler);
            InitList(_monthList, listCommandEventHandler);
 
            _weekList = new List();
            _weekList.DataMember = "6"; 
            listCommandEventHandler = new ListCommandEventHandler(this.WeekListEventHandler); 
            InitList(_weekList, listCommandEventHandler);
 
            _dayList = new List();
            _dayList.DataMember = "7";
            listCommandEventHandler = new ListCommandEventHandler(this.DayListEventHandler);
            InitList(_dayList, listCommandEventHandler); 

            // Initialize the VisibleDate which will be used to keep track 
            // the ongoing selection of year, month and day from multiple 
            // secondary UI screens.  If the page is loaded for the first
            // time, it doesn't need to be initialized (since it is not used 
            // yet) so no unnecessary viewstate value will be generated.
            if (Page.IsPostBack && Control.VisibleDate == DateTime.MinValue)
            {
                Control.VisibleDate = DateTime.Today; 
            }
        } 
 
        /// 
        public override void OnLoad(EventArgs e) 
        {
            base.OnLoad(e);

            // Here we check to see which list control should be initialized 
            // with items so postback event can be handled properly.
            if (Page.IsPostBack) 
            { 
                String controlId = Page.Request[Constants.EventSourceID];
                if (controlId != null && controlId.Length != 0) 
                {
                    List list = Page.FindControl(controlId) as List;
                    if (list != null &&
                        Control.Controls.Contains(list)) 
                    {
                        DataBindListWithEmptyValues( 
                            list, Convert.ToInt32(list.DataMember, CultureInfo.InvariantCulture)); 
                    }
                } 
            }
        }

        ///  
        public override void LoadAdapterState(Object state)
        { 
            if (state != null) 
            {
                if (state is Pair) 
                {
                    Pair pair = (Pair)state;
                    base.LoadAdapterState(pair.First);
                    _chooseOption = (int)pair.Second; 
                }
                else if (state is Triplet) 
                { 
                    Triplet triplet = (Triplet)state;
                    base.LoadAdapterState(triplet.First); 
                    _chooseOption = (int)triplet.Second;
                    Control.VisibleDate = new DateTime(Int64.Parse((String)triplet.Third, CultureInfo.InvariantCulture));
                }
                else if (state is Object[]) 
                {
                    Object[] viewState = (Object[])state; 
                    base.LoadAdapterState(viewState[0]); 
                    _chooseOption = (int)viewState[1];
                    Control.VisibleDate = new DateTime(Int64.Parse((String)viewState[2], CultureInfo.InvariantCulture)); 
                    _eraCount = (int)viewState[3];

                    if (SecondaryUIMode == TypeDate)
                    { 
                        // Create a placeholder list for capturing the selected era
                        // in postback data. 
                        for (int i = 0; i < _eraCount; i++) 
                        {
                            _selectList.Items.Add(String.Empty); 
                        }
                    }
                }
                else 
                {
                    _chooseOption = (int)state; 
                } 
            }
        } 

        /// 
        public override Object SaveAdapterState()
        { 
            DateTime visibleDate = Control.VisibleDate;
 
            bool saveVisibleDate = visibleDate != DateTime.MinValue && 
                                        DateTime.Compare(visibleDate, DateTime.Today) != 0 &&
                                        !IsViewStateEnabled(); 
            Object baseState = base.SaveAdapterState();

            if (baseState == null && !saveVisibleDate && _eraCount == 0)
            { 
                if (_chooseOption != FirstPrompt)
                { 
                    return _chooseOption; 
                }
                else 
                {
                    return null;
                }
            } 
            else if (!saveVisibleDate && _eraCount == 0)
            { 
                return new Pair(baseState, _chooseOption); 
            }
            else if (_eraCount == 0) 
            {
                return new Triplet(baseState, _chooseOption, visibleDate.Ticks.ToString(CultureInfo.InvariantCulture));
            }
            else 
            {
                return new Object[] { baseState, 
                                      _chooseOption, 
                                      visibleDate.Ticks.ToString(CultureInfo.InvariantCulture),
                                      _eraCount }; 
            }
        }

        ///  
        public override void OnPreRender(EventArgs e)
        { 
            base.OnPreRender(e); 

            // We specially binding eras of the current calendar object here 
            // when the UI of typing date is display.  We do it only if the
            // calendar supports more than one era.
            if (SecondaryUIMode == TypeDate)
            { 
                DateTimeFormatInfo currentInfo = DateTimeFormatInfo.CurrentInfo;
 
                int [] ints = currentInfo.Calendar.Eras; 

                if (ints.Length > 1) 
                {
                    // Save the value in private view state
                    _eraCount = ints.Length;
 
                    int currentEra;
                    if (_selectList.SelectedIndex != -1) 
                    { 
                        currentEra = ints[_selectList.SelectedIndex];
                    } 
                    else
                    {
                        currentEra =
                            currentInfo.Calendar.GetEra(Control.VisibleDate); 
                    }
 
                    // Clear the placeholder item list if created in LoadAdapterState 
                    _selectList.Items.Clear();
 
                    for (int i = 0; i < ints.Length; i++)
                    {
                        int era = ints[i];
 
                        _selectList.Items.Add(currentInfo.GetEraName(era));
 
                        // There is no association between the era value and 
                        // its index in the era array, so we need to check it
                        // explicitly for the default selected index. 
                        if (currentEra == era)
                        {
                            _selectList.SelectedIndex = i;
                        } 
                    }
                    _selectList.Visible = true; 
                } 
                else
                { 
                    // disable viewstate since no need to save any data for
                    // this control
                    _selectList.EnableViewState = false;
                } 
            }
            else 
            { 
                _selectList.EnableViewState = false;
            } 
        }

        /// 
        public override void Render(HtmlMobileTextWriter writer) 
        {
            ArrayList arr; 
            DateTime tempDate; 
            DateTimeFormatInfo currentDateTimeInfo = DateTimeFormatInfo.CurrentInfo;
            String abbreviatedMonthDayPattern = AbbreviateMonthPattern(currentDateTimeInfo.MonthDayPattern); 
            _threadCalendar = currentDateTimeInfo.Calendar;
            bool breakAfter = false;

            writer.EnterStyle(Style); 

            Debug.Assert(NotSecondaryUI == NotSecondaryUIInit); 
            switch (SecondaryUIMode) 
            {
                case FirstPrompt: 
                    String promptText = Control.CalendarEntryText;
                    if (String.IsNullOrEmpty(promptText))
                    {
                        promptText = SR.GetString(SR.CalendarAdapterFirstPrompt); 
                    }
 
                    // Link to input option selection screen 
                    RenderPostBackEventAsAnchor(writer,
                                                OptionPrompt.ToString(CultureInfo.InvariantCulture), 
                                                promptText);

                    // We should honor BreakAfter property here as the first
                    // UI is shown with other controls on the same form. 
                    // For other secondary UI, it is not necessary.
                    if (Control.BreakAfter) 
                    { 
                        breakAfter = true;
                    } 
                    break;

                // Render the first secondary page that provides differnt
                // options to select a date. 
                case OptionPrompt:
                    writer.Write(SR.GetString(SR.CalendarAdapterOptionPrompt)); 
                    writer.WriteBreak(); 

                    arr = new ArrayList(); 

                    // Option to select the default date
                    arr.Add(Control.VisibleDate.ToString(
                        currentDateTimeInfo.ShortDatePattern, CultureInfo.CurrentCulture)); 

                    // Option to another page that can enter a date by typing 
                    arr.Add(SR.GetString(SR.CalendarAdapterOptionType)); 

                    // Options to a set of pages for selecting a date, a week 
                    // or a month by picking month/year, week and day
                    // accordingly.  Available options are determined by
                    // SelectionMode.
                    arr.Add(SR.GetString(SR.CalendarAdapterOptionChooseDate)); 

                    if (Control.SelectionMode == CalendarSelectionMode.DayWeek || 
                        Control.SelectionMode == CalendarSelectionMode.DayWeekMonth) 
                    {
                        arr.Add(SR.GetString(SR.CalendarAdapterOptionChooseWeek)); 

                        if (Control.SelectionMode == CalendarSelectionMode.DayWeekMonth)
                        {
                            arr.Add(SR.GetString(SR.CalendarAdapterOptionChooseMonth)); 
                        }
                    } 
 
                    DataBindAndRender(writer, _optionList, arr);
                    break; 

                // Render a title and textbox to capture a date entered by user
                case TypeDate:
                    if (_textBoxErrorMessage != null) 
                    {
                        writer.Write(_textBoxErrorMessage); 
                        writer.WriteBreak(); 
                    }
 
                    if (_selectList.Visible)
                    {
                        writer.Write(SR.GetString(SR.CalendarAdapterOptionEra));
                        writer.WriteBreak(); 
                        _selectList.RenderControl(writer);
                    } 
 
                    String numericDateFormat = GetNumericDateFormat();
 
                    writer.Write(SR.GetString(SR.CalendarAdapterOptionType));
                    writer.Write(":");
                    writer.WriteBreak();
                    writer.Write("("); 
                    writer.Write(numericDateFormat.ToUpper(CultureInfo.InvariantCulture));
                    writer.Write(")"); 
 
                    if (!_selectList.Visible)
                    { 
                        writer.Write(GetEra(Control.VisibleDate));
                    }
                    writer.WriteBreak();
 
                    _textBox.Numeric = true;
                    _textBox.Size = numericDateFormat.Length; 
                    _textBox.MaxLength = numericDateFormat.Length; 
                    _textBox.Text = Control.VisibleDate.ToString(numericDateFormat, CultureInfo.InvariantCulture);
                    _textBox.Visible = true; 
                    _textBox.RenderControl(writer);

                    // Command button for sending the textbox value back to the server
                    _command.Text = GetDefaultLabel(OKLabel); 
                    _command.Visible = true;
                    _command.RenderControl(writer); 
 
                    break;
 
                // Render a paged list for choosing a month
                case ChooseMonth:
                    writer.Write(SR.GetString(SR.CalendarAdapterOptionChooseMonth));
                    writer.Write(":"); 
                    writer.WriteBreak();
 
                    tempDate = Control.VisibleDate; 

                    String abbreviatedYearMonthPattern = AbbreviateMonthPattern(currentDateTimeInfo.YearMonthPattern); 

                    // This is to be consistent with ASP.NET Calendar control
                    // on handling YearMonthPattern:
                    // Some cultures have a comma in their YearMonthPattern, 
                    // which does not look right in a calendar.  Here we
                    // strip the comma off. 
                    int indexComma = abbreviatedYearMonthPattern.IndexOf(','); 
                    if (indexComma >= 0)
                    { 
                        abbreviatedYearMonthPattern =
                            abbreviatedYearMonthPattern.Remove(indexComma, 1);
                    }
 
                    arr = new ArrayList();
                    for (int i = 0; i < _monthsToDisplay; i++) 
                    { 
                        arr.Add(tempDate.ToString(abbreviatedYearMonthPattern, CultureInfo.CurrentCulture));
                        tempDate = _threadCalendar.AddMonths(tempDate, 1); 
                    }
                    arr.Add(GetDefaultLabel(NextLabel));
                    arr.Add(GetDefaultLabel(PreviousLabel));
 
                    DataBindAndRender(writer, _monthList, arr);
                    break; 
 
                // Based on the month selected in case ChooseMonth above, render a list of
                // availabe weeks of the month. 
                case ChooseWeek:
                    String monthFormat = (GetNumericDateFormat()[0] == 'y') ? "yyyy/M" : "M/yyyy";
                    writer.Write(SR.GetString(SR.CalendarAdapterOptionChooseWeek));
                    writer.Write(" ("); 
                    writer.Write(Control.VisibleDate.ToString(monthFormat, CultureInfo.CurrentCulture));
                    writer.Write("):"); 
                    writer.WriteBreak(); 

                    // List weeks of days of the selected month.  May include 
                    // days from the previous and the next month to fill out
                    // all six week choices.  This is consistent with the
                    // ASP.NET Calendar control.
 
                    // Note that the event handling code of this list control
                    // should be implemented according to the index content 
                    // generated here. 

                    tempDate = FirstCalendarDay(Control.VisibleDate); 

                    arr = new ArrayList();
                    String weekDisplay;
                    for (int i = 0; i < 6; i++) 
                    {
                        weekDisplay = tempDate.ToString(abbreviatedMonthDayPattern, CultureInfo.CurrentCulture); 
                        weekDisplay += DaySeparator; 
                        tempDate = _threadCalendar.AddDays(tempDate, 6);
                        weekDisplay += tempDate.ToString(abbreviatedMonthDayPattern, CultureInfo.CurrentCulture); 
                        arr.Add(weekDisplay);
                        tempDate = _threadCalendar.AddDays(tempDate, 1);
                    }
 
                    DataBindAndRender(writer, _weekList, arr);
                    break; 
 
                // Based on the month and week selected in case ChooseMonth and ChooseWeek above,
                // render a list of the dates in the week. 
                case ChooseDay:
                    writer.Write(SR.GetString(SR.CalendarAdapterOptionChooseDate));
                    writer.Write(":");
                    writer.WriteBreak(); 

                    tempDate = Control.VisibleDate; 
 
                    arr = new ArrayList();
                    String date; 
                    String dayName;
                    StringBuilder dayDisplay = new StringBuilder();
                    bool dayNameFirst = (GetNumericDateFormat()[0] != 'y');
 
                    for (int i = 0; i < 7; i++)
                    { 
                        date = tempDate.ToString(abbreviatedMonthDayPattern, CultureInfo.CurrentCulture); 

                        if (Control.ShowDayHeader) 
                        {
                            // Use the short format for displaying day name
                            dayName = GetAbbreviatedDayName(tempDate);
                            dayDisplay.Length = 0; 

                            if (dayNameFirst) 
                            { 
                                dayDisplay.Append(dayName);
                                dayDisplay.Append(Space); 
                                dayDisplay.Append(date);
                            }
                            else
                            { 
                                dayDisplay.Append(date);
                                dayDisplay.Append(Space); 
                                dayDisplay.Append(dayName); 
                            }
                            arr.Add(dayDisplay.ToString()); 
                        }
                        else
                        {
                            arr.Add(date); 
                        }
                        tempDate = _threadCalendar.AddDays(tempDate, 1); 
                    } 

                    DataBindAndRender(writer, _dayList, arr); 
                                        break;

                default:
                    Debug.Assert(false, "Unexpected Secondary UI Mode"); 
                                        break;
            } 
 
            writer.ExitStyle(Style, breakAfter);
        } 

        /// 
        public override bool HandlePostBackEvent(String eventArgument)
        { 
            // This is mainly to capture the option picked by the user on
            // secondary pages and manipulate SecondaryUIMode accordingly so 
            // Render() can generate the appropriate UI. 
            // It also capture the state "Done" which can be set when a date,
            // a week or a month is selected or entered in some secondary 
            // page.

            SecondaryUIMode = Int32.Parse(eventArgument, CultureInfo.InvariantCulture);
 
            Debug.Assert(NotSecondaryUI == NotSecondaryUIInit);
            switch (SecondaryUIMode) 
            { 
            case DefaultDateDone:
                SelectRange(Control.VisibleDate, Control.VisibleDate); 
                goto case Done;

            case TypeDate:
                _requireFormTag = true; 
                break;
 
            case TypeDateDone: 
                try
                { 
                    String dateText = _textBox.Text;
                    String dateFormat = GetNumericDateFormat();
                    DateTimeFormatInfo currentInfo = DateTimeFormatInfo.CurrentInfo;
                    int eraIndex = _selectList.SelectedIndex; 

                    if (eraIndex >= 0 && 
                        eraIndex < currentInfo.Calendar.Eras.Length) 
                    {
                        dateText += currentInfo.GetEraName(currentInfo.Calendar.Eras[eraIndex]); 
                        dateFormat += "gg";
                    }

                    DateTime dateTime = DateTime.ParseExact(dateText, dateFormat, null); 
                    SelectRange(dateTime, dateTime);
                    Control.VisibleDate = dateTime; 
                } 
                catch
                { 
                    _textBoxErrorMessage = SR.GetString(SR.CalendarAdapterTextBoxErrorMessage);
                    SecondaryUIMode = TypeDate;
                    goto case TypeDate;
                } 
                goto case Done;
 
            case Done: 
                // Set the secondary exit code and raise the selection event for
                // web page developer to manipulate the selected date. 
                ExitSecondaryUIMode();
                _chooseOption = FirstPrompt;
                break;
 
            case DateOption:
            case WeekOption: 
            case MonthOption: 
                _chooseOption = SecondaryUIMode;  // save in the ViewState
 
                // In all 3 cases, continue to the UI that chooses a month
                SecondaryUIMode = ChooseMonth;
                break;
            } 

            return true; 
        } 

        ///////////////////////////////////////////////////////////////////// 
        // Misc. helper and wrapper functions
        /////////////////////////////////////////////////////////////////////

        private int MonthsToDisplay(int screenCharactersHeight) 
        {
            const int MinMonthsToDisplay = 4; 
            const int MaxMonthsToDisplay = 12; 

            if (screenCharactersHeight < MinMonthsToDisplay) 
            {
                return MinMonthsToDisplay;
            }
            else if (screenCharactersHeight > MaxMonthsToDisplay) 
            {
                return MaxMonthsToDisplay; 
            } 
            return screenCharactersHeight;
        } 

        // A helper function to initialize and add a child list control
        private void InitList(List list,
                              ListCommandEventHandler eventHandler) 
        {
            list.Visible = false; 
            list.ItemCommand += eventHandler; 
            list.EnableViewState = false;
            Control.Controls.Add(list); 
        }

        private void DataBindListWithEmptyValues(List list, int arraySize)
        { 
            ArrayList arr = new ArrayList();
            for (int i = 0; i < arraySize; i++) 
            { 
                arr.Add("");
            } 
            list.DataSource = arr;
            list.DataBind();
        }
 
        // A helper function to do the common code for DataBind and
        // RenderChildren. 
        private void DataBindAndRender(HtmlMobileTextWriter writer, 
                                       List list,
                                       ArrayList arr) 
        {
            list.DataSource = arr;
            list.DataBind();
            list.Visible = true; 
            list.RenderControl(writer);
        } 
 
        // Abbreviate the Month format from "MMMM" (full
        // month name) to "MMM" (three-character month abbreviation) 
        private String AbbreviateMonthPattern(String pattern)
        {
            const String FullMonthFormat = "MMMM";
 
            int i = pattern.IndexOf(FullMonthFormat, StringComparison.Ordinal);
            if (i != -1) 
            { 
                pattern = pattern.Remove(i, 1);
            } 
            return pattern;
        }

        private String GetAbbreviatedDayName(DateTime dateTime) 
        {
            return DateTimeFormatInfo.CurrentInfo.GetAbbreviatedDayName( 
                        _threadCalendar.GetDayOfWeek(dateTime)); 
        }
 
        private String GetEra(DateTime dateTime)
        {
            // We shouldn't need to display the era for the common Gregorian
            // Calendar 
            if (DateTimeFormatInfo.CurrentInfo.Calendar.GetType() ==
                typeof(GregorianCalendar)) 
            { 
                return String.Empty;
            } 
            else
            {
                return dateTime.ToString("gg", CultureInfo.CurrentCulture);
            } 
        }
 
        private static readonly char[] formatChars = 
                                            new char[] { 'M', 'd', 'y' };
 
        private String GetNumericDateFormat()
        {
            String shortDatePattern =
                DateTimeFormatInfo.CurrentInfo.ShortDatePattern; 

            // Guess on what short date pattern should be used 
            int i = shortDatePattern.IndexOfAny(formatChars); 

            char firstFormatChar; 
            if (i == -1)
            {
                firstFormatChar = 'M';
            } 
            else
            { 
                firstFormatChar = shortDatePattern[i]; 
            }
 
            // We either use two or four digits for the year
            String yearPattern;
            if (shortDatePattern.IndexOf("yyyy", StringComparison.Ordinal) == -1)
            { 
                yearPattern = "yy";
            } 
            else 
            {
                yearPattern = "yyyy"; 
            }

            switch (firstFormatChar)
            { 
            case 'M':
            default: 
                return "MMdd" + yearPattern; 
            case 'd':
                return "ddMM" + yearPattern; 
            case 'y':
                return yearPattern + "MMdd";
            }
        } 

        ///////////////////////////////////////////////////////////////////// 
        // Helper functions 
        /////////////////////////////////////////////////////////////////////
 
        // Return the first date of the input year and month
        private DateTime EffectiveVisibleDate(DateTime visibleDate)
        {
            return _threadCalendar.AddDays( 
                        visibleDate,
                        -(_threadCalendar.GetDayOfMonth(visibleDate) - 1)); 
        } 

        // Return the beginning date of a calendar that includes the 
        // targeting month.  The date can actually be in the previous month.
        private DateTime FirstCalendarDay(DateTime visibleDate)
        {
            DateTime firstDayOfMonth = EffectiveVisibleDate(visibleDate); 
            int daysFromLastMonth =
                ((int)_threadCalendar.GetDayOfWeek(firstDayOfMonth)) - 
                NumericFirstDayOfWeek(); 

            // Always display at least one day from the previous month 
            if (daysFromLastMonth <= 0)
            {
                daysFromLastMonth += 7;
            } 
            return _threadCalendar.AddDays(firstDayOfMonth, -daysFromLastMonth);
        } 
 
        private int NumericFirstDayOfWeek()
        { 
            // Used globalized value by default
            return(Control.FirstDayOfWeek == FirstDayOfWeek.Default)
            ? (int) DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek
            : (int) Control.FirstDayOfWeek; 
        }
 
        ///////////////////////////////////////////////////////////////////// 
        // The followings are event handlers to capture the selection from
        // the corresponding list control in an secondary page.  The index of 
        // the selection is used to determine which and how the next
        // secondary page is rendered.  Some event handlers below update
        // Calendar.VisibleDate and set SecondaryUIMode with appropriate
        // values. 
        ////////////////////////////////////////////////////////////////////////
 
        private void TextBoxEventHandler(Object source, EventArgs e) 
        {
            HandlePostBackEvent(TypeDateDone.ToString(CultureInfo.InvariantCulture)); 
        }

        private static readonly int[] Options =
            {DefaultDateDone, TypeDate, DateOption, WeekOption, MonthOption}; 

        private void OptionListEventHandler(Object source, ListCommandEventArgs e) 
        { 
            SecondaryUIMode = Options[e.ListItem.Index];
            HandlePostBackEvent(SecondaryUIMode.ToString(CultureInfo.InvariantCulture)); 
        }

        private void MonthListEventHandler(Object source, ListCommandEventArgs e)
        { 
            _threadCalendar = DateTimeFormatInfo.CurrentInfo.Calendar;
 
            if (e.ListItem.Index == _monthsToDisplay) 
            {
                // Next was selected 
                Control.VisibleDate = _threadCalendar.AddMonths(
                                        Control.VisibleDate, _monthsToDisplay);
                SecondaryUIMode = ChooseMonth;
            } 
            else if (e.ListItem.Index == _monthsToDisplay + 1)
            { 
                // Prev was selected 
                Control.VisibleDate = _threadCalendar.AddMonths(
                                        Control.VisibleDate, -_monthsToDisplay); 
                SecondaryUIMode = ChooseMonth;
            }
            else
            { 
                // A month was selected
                Control.VisibleDate = _threadCalendar.AddMonths( 
                                        Control.VisibleDate, 
                                        e.ListItem.Index);
 
                if (_chooseOption == MonthOption)
                {
                    // Add the whole month to the date list
                    DateTime beginDate = EffectiveVisibleDate(Control.VisibleDate); 
                    Control.VisibleDate = beginDate;
 
                    DateTime endDate = _threadCalendar.AddMonths(beginDate, 1); 
                    endDate = _threadCalendar.AddDays(endDate, -1);
 
                    SelectRange(beginDate, endDate);
                    HandlePostBackEvent(Done.ToString(CultureInfo.InvariantCulture));
                }
                else 
                {
                    SecondaryUIMode = ChooseWeek; 
                } 
            }
        } 

        private void WeekListEventHandler(Object source, ListCommandEventArgs e)
        {
            // Get the first calendar day and adjust it to the week the user 
            // selected (to be consistent with the index setting in Render())
            _threadCalendar = DateTimeFormatInfo.CurrentInfo.Calendar; 
 
            DateTime tempDate = FirstCalendarDay(Control.VisibleDate);
 
            Control.VisibleDate = _threadCalendar.AddDays(tempDate, e.ListItem.Index * 7);

            if (_chooseOption == WeekOption)
            { 
                // Add the whole week to the date list
                DateTime endDate = _threadCalendar.AddDays(Control.VisibleDate, 6); 
 
                SelectRange(Control.VisibleDate, endDate);
                HandlePostBackEvent(Done.ToString(CultureInfo.InvariantCulture)); 
            }
            else
            {
                SecondaryUIMode = ChooseDay; 
            }
        } 
 
        private void DayListEventHandler(Object source, ListCommandEventArgs e)
        { 
            _threadCalendar = DateTimeFormatInfo.CurrentInfo.Calendar;

            // VisibleDate should have been set with the first day of the week
            // so the selected index can be used to adjust to the selected day. 
            Control.VisibleDate = _threadCalendar.AddDays(Control.VisibleDate, e.ListItem.Index);
 
            SelectRange(Control.VisibleDate, Control.VisibleDate); 
            HandlePostBackEvent(Done.ToString(CultureInfo.InvariantCulture));
        } 

        private void SelectRange(DateTime dateFrom, DateTime dateTo)
        {
            Debug.Assert(dateFrom <= dateTo, "Bad Date Range"); 

            // see if this range differs in any way from the current range 
            // these checks will determine this because the colleciton is sorted 
            TimeSpan ts = dateTo - dateFrom;
            SelectedDatesCollection selectedDates = Control.SelectedDates; 
            if (selectedDates.Count != ts.Days + 1
                || selectedDates[0] != dateFrom
                || selectedDates[selectedDates.Count - 1] != dateTo)
            { 
                selectedDates.SelectRange(dateFrom, dateTo);
                Control.RaiseSelectionChangedEvent(); 
            } 
        }
 
        private bool IsViewStateEnabled()
        {
            Control ctl = Control;
            while (ctl != null) 
            {
                if (!ctl.EnableViewState) 
                { 
                    return false;
                } 
                ctl = ctl.Parent;
            }
            return true;
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.


                        

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