DatePeriodEdit

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports DevExpress.XtraEditors.Registrator
Imports System.ComponentModel
Imports DevExpress.XtraEditors.ViewInfo
Imports DevExpress.XtraEditors.Drawing
Imports DevExpress.XtraEditors
Imports DevExpress.XtraEditors.Repository
Imports DevExpress.XtraEditors.Popup
Imports DevExpress.XtraEditors.Controls
Imports DevExpress.XtraEditors.Calendar
Imports System.Windows.Forms
Imports System.Drawing
Imports DevExpress.Utils.Serializing
Imports System.Globalization
Imports DevExpress.Utils
Imports DevExpress.Data.Utils
Imports System.Collections
<UserRepositoryItem("RegisterDatePeriodEdit")> _
Public Class RepositoryItemDatePeriodEdit
    Inherits RepositoryItemDateEdit
    Private _AllowedDateRange() As Date
    Private _OptionsSelection As OptionsSelection
    Private _PeriodsStoreMode As StoreMode
    Private _SeparatorChar As Char = ","c
    Public Const DatePeriodEditName As String = "DatePeriodEdit"
    Shared Sub New()
        RegisterDatePeriodEdit()
    End Sub
    Public Sub New()
        _OptionsSelection = New OptionsSelection()
        TextEditStyle = TextEditStyles.DisableTextEditor
    End Sub
    Public Overrides ReadOnly Property EditorTypeName() As String
        Get
            Return DatePeriodEditName
        End Get
    End Property
    Public Shared Sub RegisterDatePeriodEdit()
        EditorRegistrationInfo.Default.Editors.Add(New EditorClassInfo(DatePeriodEditName, GetType(DatePeriodEdit), GetType(RepositoryItemDatePeriodEdit), GetType(DateEditViewInfo), New ButtonEditPainter(), True))
    End Sub
    <Description("Gets or sets how the editor store periods selected via the calendar ."), Category(CategoryName.Format), DefaultValue(StoreMode.Default)> _
    Public Overridable Property PeriodsStoreMode() As StoreMode
        Get
            Return _PeriodsStoreMode
        End Get
        Set(ByVal value As StoreMode)
            If PeriodsStoreMode = value Then
                Return
            End If
            Me._PeriodsStoreMode = value
        End Set
    End Property
    <Description("Gets or sets the character separating periods"), Category(CategoryName.Format), DefaultValue(","c)> _
    Public Overridable Property SeparatorChar() As Char
        Get
            Return Me._SeparatorChar
        End Get
        Set(ByVal value As Char)
            If SeparatorChar = value Then
                Return
            End If
            Me._SeparatorChar = value
            OnPropertiesChanged()
        End Set
    End Property
    <Browsable(False)> _
    Public Overrides ReadOnly Property Mask() As DevExpress.XtraEditors.Mask.MaskProperties
        Get
            Return MyBase.Mask
        End Get
    End Property
    <Browsable(False)> _
    Public Overrides ReadOnly Property EditFormat() As FormatInfo
        Get
            Return MyBase.DisplayFormat
        End Get
    End Property
    <Browsable(False)> _
    Public Shadows ReadOnly Property VistaEditTime() As DefaultBoolean
        Get
            Return MyBase.VistaEditTime
        End Get
    End Property
    <Browsable(False)> _
    Public Shadows ReadOnly Property VistaDisplayMode() As DefaultBoolean
        Get
            Return MyBase.VistaDisplayMode
        End Get
    End Property
    <Browsable(False)> _
    Public Shadows ReadOnly Property EditMask() As String
        Get
            Return MyBase.EditMask
        End Get
    End Property
    <Description("Provides access to the settings used to selection."), Category(CategoryName.Properties), DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> _
    Public ReadOnly Property OptionsSelection() As OptionsSelection
        Get
            Return _OptionsSelection
        End Get
    End Property
    Public Property AllowedDateRange() As Date()
        Get
            Return Me._AllowedDateRange
        End Get
        Set(ByVal value As Date())
            Me._AllowedDateRange = value
        End Set
    End Property
    Public Overrides Sub Assign(ByVal item As RepositoryItem)
        MyBase.Assign(item)
        Dim source As RepositoryItemDatePeriodEdit = TryCast(item, RepositoryItemDatePeriodEdit)
        Me._OptionsSelection = source.OptionsSelection
        Me._SeparatorChar = source.SeparatorChar
        Me._PeriodsStoreMode = source.PeriodsStoreMode
    End Sub
    Protected Overrides Function IsNullValue(ByVal editValue As Object) As Boolean
        If TypeOf editValue Is PeriodsSet Then
            Return (CType(editValue, PeriodsSet)).Periods.Count = 0
        End If
        If TypeOf editValue Is String Then
            Dim [set] As PeriodsSet = PeriodsSet.Parse(CStr(editValue))
            If [set] IsNot Nothing Then
                Return [set].Periods.Count = 0
            End If
        End If
        Return False
    End Function
    Public Overloads Overrides Function GetDisplayText(ByVal format As FormatInfo, ByVal editValue As Object) As String
        Dim displayText As String = String.Empty
        Dim [set] As PeriodsSet = TryCast(editValue, PeriodsSet)
        If [set] IsNot Nothing Then
            displayText = [set].ToString(format.FormatString, SeparatorChar)
        Else
            If TypeOf editValue Is String Then
                displayText = PeriodsSet.Parse(CStr(editValue)).ToString(format.FormatString, SeparatorChar)
            End If
        End If
        Dim e As New CustomDisplayTextEventArgs(editValue, displayText)
        If format IsNot EditFormat Then
            RaiseCustomDisplayText(e)
        End If
        Return e.DisplayText
    End Function
End Class
Public Class DatePeriodEdit
    Inherits DateEdit
    Shared Sub New()
        RepositoryItemDatePeriodEdit.RegisterDatePeriodEdit()
    End Sub
    Public Sub New()
        MyBase.New()
        EditValue = New PeriodsSet()
    End Sub
    Public Overrides Property EditValue() As Object
        Get
            Dim value As PeriodsSet = TryCast(MyBase.EditValue, PeriodsSet)
            If Properties.PeriodsStoreMode = StoreMode.String Then
                If value IsNot Nothing Then
                    Return value.ToString()
                Else
                    Return String.Empty
                End If
            Else
                If value IsNot Nothing Then
                    Return value
                Else
                    Return New PeriodsSet()
                End If
            End If
        End Get
        Set(ByVal value As Object)
            If TypeOf value Is PeriodsSet Then
                MyBase.EditValue = value
                Return
            End If
            If TypeOf value Is String Then
                MyBase.EditValue = PeriodsSet.Parse(CStr(value))
                Return
            End If
            MyBase.EditValue = value
        End Set
    End Property
    Public Overrides ReadOnly Property EditorTypeName() As String
        Get
            Return RepositoryItemDatePeriodEdit.DatePeriodEditName
        End Get
    End Property
    <DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> _
    Public Shadows ReadOnly Property Properties() As RepositoryItemDatePeriodEdit
        Get
            Return TryCast(MyBase.Properties, RepositoryItemDatePeriodEdit)
        End Get
    End Property
    Protected Overrides Function CreatePopupForm() As PopupBaseForm
        Return New VistaPopupDatePeriodEditForm(Me)
    End Function
    Protected Overrides Function ExtractParsedValue(ByVal e As ConvertEditValueEventArgs) As Object
        Return e.Value
    End Function
End Class
Public Class VistaPopupDatePeriodEditForm
    Inherits VistaPopupDateEditForm
    Public Sub New(ByVal ownerEdit As DatePeriodEdit)
        MyBase.New(ownerEdit)
    End Sub
    Protected Overrides Function CreateCalendar() As DateEditCalendar
        Dim c As New VistaDatePeriodEditCalendar(OwnerEdit.Properties, OwnerEdit.EditValue)
        AddHandler c.OkClick, AddressOf OnOkClick
        Return c
    End Function
    Public Overrides ReadOnly Property ResultValue() As Object
        Get
            Return Calendar.TotalPeriods.GetCopy()
        End Get
    End Property
    Public Overridable Shadows ReadOnly Property Calendar() As VistaDatePeriodEditCalendar
        Get
            Return TryCast(MyBase.Calendar, VistaDatePeriodEditCalendar)
        End Get
    End Property
End Class
Public Class VistaDatePeriodEditCalendar
    Inherits VistaDateEditCalendar
    Private _TotalPeriods, _TotalPeriodsCopy As PeriodsSet
    Private _AllowMark As Boolean
    Private _ViewLevel As ViewLevel
    Public Sub New(ByVal item As RepositoryItemDatePeriodEdit, ByVal editDate As Object)
        MyBase.New(item, editDate)
        Selection.Clear()
        Multiselect = True
        Dim editValue As PeriodsSet = TryCast(Properties.OwnerEdit.EditValue, PeriodsSet)
        _TotalPeriods = New PeriodsSet()
        _ViewLevel = GetNewLevel(Properties.OptionsSelection.DefaultLevel, Properties.OptionsSelection.DefaultLevel)
        CreatePrevImage(False)
    End Sub
    Public Overrides Sub ResetState(ByVal editDate As Object, ByVal dt As DateTime)
        UpdateTotalPeriods(editDate)
        MyBase.ResetState(editDate, dt)
        If TotalPeriods.Periods.Count = 0 Then
            DateTime = Date.Now
        Else
            DateTime = TotalPeriods(0).Begin
        End If
        ViewLevel = GetNewLevel(ViewLevel, ViewLevel)
    End Sub
    Public Overridable Shadows Property DateTime() As DateTime
        Get
            Return MyBase.DateTime.Date
        End Get
        Set(ByVal value As DateTime)
            MyBase.DateTime = value.Date
        End Set
    End Property
    Protected Overridable Sub UpdateTotalPeriods(ByVal value As Object)
        Dim editValue As PeriodsSet = TryCast(value, PeriodsSet)
        TotalPeriods.Periods.Clear()
        If editValue IsNot Nothing Then
            TotalPeriods = editValue.GetCopy()
        Else
            If TypeOf value Is String Then
                TotalPeriods = PeriodsSet.Parse(CStr(value))
            End If
        End If
    End Sub
    Protected Overridable ReadOnly Property CtrlKeyPressed() As Boolean
        Get
            Return (System.Windows.Forms.Control.ModifierKeys And Keys.Control) <> 0
        End Get
    End Property
    Protected Overrides Sub OnDateTimeCommit(ByVal value As Object, ByVal cleared As Boolean)
    End Sub
    Protected Friend Overridable Shadows ReadOnly Property Properties() As RepositoryItemDatePeriodEdit
        Get
            Return TryCast(MyBase.Properties, RepositoryItemDatePeriodEdit)
        End Get
    End Property
    Protected Friend Overridable Function GetSwitchState() As Boolean
        Return SwitchState
    End Function
    Protected Overrides Function CreateInfoArgs() As DateEditInfoArgs
        Return New VistaDatePeriodEditInfoArgs(Me)
    End Function
    Protected Overrides Function CreatePainter() As DateEditPainter
        Return New VistaDatePeriodEditPainter(Me)
    End Function
    Protected Overrides Function CreateSelectionState() As DateEditCalendarStateBase
        Return New VistaDatePeriodEditCalendarSelectState(Me)
    End Function
    Public Overridable Property TotalPeriods() As PeriodsSet
        Get
            Return _TotalPeriods
        End Get
        Set(ByVal value As PeriodsSet)
            _TotalPeriods = value
        End Set
    End Property
    Protected Friend Overridable Function GetDayCells() As DayNumberCellInfoCollection
        Return Calendars(0).DayCells
    End Function
    Protected Overrides Sub OnMoveVertical(ByVal dir As Integer)
    End Sub
    Protected Overrides Sub OnMoveHorizontal(ByVal dir As Integer)
    End Sub
    Protected Overrides Sub SetViewCore(ByVal v As DateEditCalendarViewType)
    End Sub
    Public Overrides Property View() As DateEditCalendarViewType
        Get
            Return ConvertViewLevelToView(ViewLevel)
        End Get
        Set(ByVal value As DateEditCalendarViewType)
        End Set
    End Property
    Protected Overrides Sub SetSelection(ByVal [date] As DateTime)
    End Sub
    Protected Overloads Overrides Sub SetSelectionRange(ByVal [date] As DateTime)
    End Sub
    Public Overridable Property ViewLevel() As ViewLevel
        Get
            Return _ViewLevel
        End Get
        Set(ByVal value As ViewLevel)
            Dim newValue As ViewLevel = GetNewLevel(value, ViewLevel)
            Dim oldValue As ViewLevel = ViewLevel
            If oldValue = newValue Then
                Return
            End If
            Dim oldView, newView As DateEditCalendarViewType
            If oldValue = ViewLevel.Days AndAlso newValue = ViewLevel.Weeks Then
                oldView = DateEditCalendarViewType.MonthInfo
                newView = DateEditCalendarViewType.YearInfo
            Else
                oldView = ConvertViewLevelToView(oldValue)
                newView = ConvertViewLevelToView(newValue)
            End If
            OnViewChanging(oldView, newView)
            _ViewLevel = newValue
            OnViewChanged(oldView, newView)
        End Set
    End Property
    Protected Overridable Function GetNewLevel(ByVal newLevel As ViewLevel, ByVal currentLevel As ViewLevel) As ViewLevel
        Dim lowLevel As ViewLevel = Properties.OptionsSelection.LowLevel
        Dim highLevel As ViewLevel = Properties.OptionsSelection.HightLevel
        If (Not Properties.OptionsSelection.ShowWeekLevel) Then
            If lowLevel = ViewLevel.Weeks Then
                lowLevel = ViewLevel.Months
            End If
            If highLevel = ViewLevel.Weeks Then
                highLevel = ViewLevel.Days
            End If
        End If
        If lowLevel > highLevel Then
            Return currentLevel
        End If
        If newLevel < lowLevel Then
            Return lowLevel
        End If
        If newLevel > highLevel Then
            Return highLevel
        End If
        Return newLevel
    End Function
    Public Overridable Sub ViewLevelUp()
        If ViewLevel = ViewLevel.Days Then
            If Properties.OptionsSelection.ShowWeekLevel Then
                ViewLevel = ViewLevel.Weeks
            Else
                ViewLevel = ViewLevel.Months
            End If
        ElseIf ViewLevel = ViewLevel.Weeks Then
            ViewLevel = ViewLevel.Months
        Else
            ViewLevel = ViewLevel.Years
        End If
    End Sub
    Public Overridable Sub ViewLevelDown()
        If ViewLevel = ViewLevel.Years Then
            ViewLevel = ViewLevel.Months
        ElseIf ViewLevel = ViewLevel.Months Then
            If Properties.OptionsSelection.ShowWeekLevel Then
                ViewLevel = ViewLevel.Weeks
            Else
                ViewLevel = ViewLevel.Days
            End If
        Else
            ViewLevel = ViewLevel.Days
        End If
    End Sub
    Protected Overridable Function ConvertViewLevelToView(ByVal level As ViewLevel) As DateEditCalendarViewType
        If level = ViewLevel.Days Then
            Return DateEditCalendarViewType.MonthInfo
        End If
        If level = ViewLevel.Weeks Then
            Return DateEditCalendarViewType.MonthInfo
        End If
        If level = ViewLevel.Months Then
            Return DateEditCalendarViewType.YearInfo
        End If
        If level = ViewLevel.Years Then
            Return DateEditCalendarViewType.YearsInfo
        End If
        Return DateEditCalendarViewType.YearsInfo
    End Function
    Protected Overridable Sub MarkSelectedDay()
        If Selection.Count = 0 Then
            Return
        End If
        MarkPeriod(Selection(0), Selection(1))
    End Sub
    Protected Overridable Sub MarkPeriod(ByVal begin As DateTime, ByVal [end] As DateTime)
        If Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Merging Then
            TotalPeriods.MergeWith(begin, [end])
        ElseIf Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Intersection Then
            TotalPeriods.IntersectWith(begin, [end])
        ElseIf Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Disabled Then
            If (Not TotalPeriods.ContainPeriod(begin, [end])) Then
                TotalPeriods.Periods.Clear()
            End If
            TotalPeriods.IntersectWith(begin, [end])
        End If
        UpdateSelection()
        Selection.Clear()
    End Sub
    Protected Friend Overridable Sub UpdateSelection()
        UpdateExistingCellsState()
        Invalidate()
    End Sub
    Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
        MyBase.OnMouseDown(e)
        Dim hit As CalendarHitInfo = GetHitInfo(e)
        _TotalPeriodsCopy = _TotalPeriods.GetCopy()
        If (Not CtrlKeyPressed) Then
            If (hit.InfoType = CalendarHitInfoType.Item) OrElse hit.InfoType = CalendarHitInfoType.WeekNumber OrElse hit.InfoType = CalendarHitInfoType.Unknown Then
                TotalPeriods.Periods.Clear()
            End If
        End If
    End Sub
    Protected Overrides Sub OnMouseUp(ByVal e As System.Windows.Forms.MouseEventArgs)
        _AllowMark = True
        MyBase.OnMouseUp(e)
        If (Not _AllowMark) Then
            Return
        End If
        MarkSelectedDay()
    End Sub
    Protected Overrides Sub OnItemClick(ByVal hitInfo As CalendarHitInfo)
        Dim cell As DayNumberCellInfo = TryCast(hitInfo.HitObject, DayNumberCellInfo)
        If cell IsNot Nothing Then
            ChangeDateOnItemClick(cell)
            If ViewLevel = Properties.OptionsSelection.LowLevel OrElse (CtrlKeyPressed AndAlso Properties.OptionsSelection.MultiselectBehaviour <> MultiselectBehaviour.Disabled) Then
                MarkItemOnClick(cell)
            Else
                TotalPeriods = _TotalPeriodsCopy.GetCopy()
                ViewLevelDown()
            End If
        End If
    End Sub
    Protected Overridable Sub MarkItemOnClick(ByVal cell As DayNumberCellInfo)
        Dim begin As DateTime = CalcPeriodBeginDateTime(cell.Date)
        If ViewLevel = ViewLevel.Days Then
            MarkPeriod(begin, CalcPeriodEndDateTime(begin, ViewLevel))
        ElseIf ViewLevel = ViewLevel.Weeks Then
            MarkPeriod(begin, CalcPeriodEndDateTime(begin, ViewLevel))
        ElseIf ViewLevel = ViewLevel.Months Then
            MarkPeriod(begin, CalcPeriodEndDateTime(begin, ViewLevel))
        ElseIf ViewLevel = ViewLevel.Years Then
            MarkPeriod(begin, CalcPeriodEndDateTime(begin, ViewLevel))
        End If
    End Sub
    Protected Overridable Sub ChangeDateOnItemClick(ByVal cell As DayNumberCellInfo)
        If _ViewLevel = ViewLevel.Weeks Then
            Return
        End If
        Dim maxDate As DateTime = DateTime
        If cell.Date.Month <> DateTime.Month Then
            maxDate = cell.Date
        Else
            maxDate = CalcPeriodEndDateTime(cell.Date, ViewLevel)
        End If
        If _ViewLevel < ViewLevel.Months Then
            If DateTime.Month < maxDate.Month Then
                If DateTime.Year = maxDate.Year Then
                    OnRightArrowClick()
                Else
                    OnLeftArrowClick()
                End If
            ElseIf DateTime.Month > maxDate.Month Then
                If DateTime.Year = maxDate.Year Then
                    OnLeftArrowClick()
                Else
                    OnRightArrowClick()
                End If
            End If
            Return
        End If
        If ViewLevel = ViewLevel.Days Then
            DateTime = New DateTime(cell.Date.Year, cell.Date.Month, CorrectDay(DateTime.Year, cell.Date.Month, cell.Date.Day), 0, 0, 0)
        ElseIf ViewLevel = ViewLevel.Weeks Then
            DateTime = New DateTime(cell.Date.Year, cell.Date.Month, CorrectDay(DateTime.Year, cell.Date.Month, DateTime.Day), 0, 0, 0)
        ElseIf ViewLevel = ViewLevel.Months Then
            DateTime = New DateTime(DateTime.Year, cell.Date.Month, CorrectDay(DateTime.Year, cell.Date.Month, DateTime.Day), 0, 0, 0)
        ElseIf ViewLevel = ViewLevel.Years Then
            DateTime = New DateTime(cell.Date.Year, DateTime.Month, CorrectDay(cell.Date.Year, DateTime.Month, DateTime.Day), 0, 0, 0)
        End If
    End Sub
    Protected Overrides Sub ProcessClick(ByVal hit As CalendarHitInfo)
        _AllowMark = False
        MyBase.ProcessClick(hit)
        If hit.InfoType = CalendarHitInfoType.WeekNumber Then
            onWeekNuberClick(hit)
        End If
    End Sub
    Protected Overrides Sub IncView()
        ViewLevelUp()
    End Sub
    Protected Overrides Sub DecView()
        ViewLevelDown()
    End Sub
    Protected Overridable Sub onWeekNuberClick(ByVal hit As CalendarHitInfo)
        Dim week As DayNumberCellInfo = TryCast(hit.HitObject, DayNumberCellInfo)
        If week IsNot Nothing AndAlso Properties.OptionsSelection.MultiselectBehaviour <> MultiselectBehaviour.Disabled Then
            MarkPeriod(week.Date, week.Date.AddDays(7).AddSeconds(-1))
        End If
    End Sub
    Protected Overrides Sub OnClearClick()
        TotalPeriods.Periods.Clear()
        UpdateExistingCellsState()
        Invalidate()
    End Sub
    Protected Overrides Sub OnCancelClick()
        Properties.OwnerEdit.CancelPopup()
    End Sub
    Public Overridable Function CalcPeriodBeginDateTime(ByVal beginDate As DateTime) As DateTime
        Return beginDate.Date
    End Function
    Public Overridable Function CalcPeriodEndDateTime(ByVal beginDate As DateTime, ByVal level As ViewLevel) As DateTime
        Dim endDate As DateTime = beginDate
        If level = ViewLevel.Days Then
            endDate = endDate.AddDays(1)
            endDate = endDate.AddSeconds(-1)
        ElseIf level = ViewLevel.Weeks Then
            endDate = endDate.AddDays(7)
            endDate = endDate.AddSeconds(-1)
        ElseIf level = ViewLevel.Months Then
            endDate = endDate.AddMonths(1)
            endDate = endDate.AddSeconds(-1)
        ElseIf level = ViewLevel.Years Then
            endDate = endDate.AddYears(1)
            endDate = endDate.AddSeconds(-1)
        End If
        Return endDate
    End Function
    Protected Overrides Function GetStartSelectionByState(ByVal [date] As DateTime) As DateTime
        If ViewLevel = ViewLevel.Weeks Then
            Return GetFirstDayOfTheWeek([date])
        End If
        Return MyBase.GetStartSelectionByState([date])
    End Function
    Protected Overrides Function GetEndSelectionByState(ByVal dt As DateTime) As DateTime
        If ViewLevel = ViewLevel.Weeks Then
            Return GetLastDayOfTheWeek(dt)
        End If
        Return MyBase.GetEndSelectionByState(dt)
    End Function
    Protected Overridable Function GetFirstDayOfTheWeek(ByVal [date] As DateTime) As DateTime
        Dim dt As New DateTime([date].Year, [date].Month, [date].Day, 0, 0, 0)
        Do While dt.DayOfWeek <> FirstDayOfWeek
            dt = dt.AddDays(-1)
        Loop
        Return dt
    End Function
    Protected Overridable Function GetLastDayOfTheWeek(ByVal [date] As DateTime) As DateTime
        Dim dt As DateTime = GetFirstDayOfTheWeek([date])
        dt = dt.AddDays(7).AddSeconds(-1)
        Return dt
    End Function
End Class
Public Class VistaDatePeriodEditInfoArgs
    Inherits VistaDateEditInfoArgs
    Public Sub New(ByVal calendar As VistaDatePeriodEditCalendar)
        MyBase.New(calendar)
    End Sub
    Protected Overrides Function IsMultiselectDateSelected(ByVal cell As DayNumberCellInfo) As Boolean
        Dim selected As Boolean = MyBase.IsMultiselectDateSelected(cell)
        Dim patchCell As CustomDayNumberCellInfo = TryCast(cell, CustomDayNumberCellInfo)
        If patchCell IsNot Nothing Then
            Dim endDate As DateTime = Calendar.CalcPeriodEndDateTime(cell.Date, Calendar.ViewLevel)
            patchCell.Marked = Calendar.TotalPeriods.ContainPeriod(cell.Date, endDate)
            patchCell.ContainMark = Calendar.TotalPeriods.ContainPartOfPeriod(cell.Date, endDate)
            If selected Then
                If Calendar.Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Merging OrElse (Calendar.Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Intersection AndAlso patchCell.Marked = True) Then
                    patchCell.ContainMark = False
                End If
                If patchCell.Marked AndAlso Calendar.Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Intersection Then
                    selected = False
                End If
                patchCell.Marked = False
            End If
        End If
        Return selected
    End Function
    Protected Overrides Function IsDateActive(ByVal cell As DayNumberCellInfo) As Boolean
        If Calendar.ViewLevel = ViewLevel.Weeks Then
            Return True
        End If
        Return MyBase.IsDateActive(cell)
    End Function
    Protected Overloads Overrides Sub CalcItemsInfo()
        If Calendar.ViewLevel = ViewLevel.Weeks Then
            CalcWeekItemsInfo()
        Else
            MyBase.CalcItemsInfo()
        End If
    End Sub
    Protected Overridable Sub CalcWeekItemsInfo()
        DayCells.Clear()
        WeekCells.Clear()
        Dim rect As New Rectangle(New Point(DateClientRect.X + DistanceFromLeftToCell, DateClientRect.Y), New Size((DateClientRect.Width - 4) / 2, DateClientRect.Height \ 3))
        Dim currInfo As DayNumberCellInfo
        For row As Integer = 0 To 2
            For col As Integer = 0 To 1
                currInfo = CreateWeekCellInfo(row, col)
                If currInfo IsNot Nothing Then
                    currInfo.SetAppearance(Appearance)
                    currInfo.TextBounds = CalcCellTextRect(currInfo.Text, rect)
                    currInfo.Bounds = rect
                    DayCells.Add(currInfo)
                End If
                rect.Offset(rect.Width, 0)
            Next col
            rect.X = DateClientRect.X + DistanceFromLeftToCell
            rect.Offset(0, rect.Height)
        Next row
        UpdateExistingCellsState()
    End Sub
    Protected Overridable Function CreateWeekCellInfo(ByVal row As Integer, ByVal col As Integer) As DayNumberCellInfo
        Dim currInfo As DayNumberCellInfo
        Dim dt As DateTime = FirstVisibleDate.AddDays(14 * row + 7 * col)
        currInfo = New CustomDayNumberCellInfo(dt)
        Dim endDay As DateTime = currInfo.Date.AddDays(6)
        Dim dateSeparator As String = " "
        currInfo.Text = Calendar.DateFormat.GetAbbreviatedMonthName(currInfo.Date.Month) & dateSeparator & currInfo.Date.Day & " - " & Calendar.DateFormat.GetAbbreviatedMonthName(endDay.Month) & dateSeparator & endDay.Day
        Return currInfo
    End Function
    Public Overridable Shadows ReadOnly Property Calendar() As VistaDatePeriodEditCalendar
        Get
            Return TryCast(MyBase.Calendar, VistaDatePeriodEditCalendar)
        End Get
    End Property
    Protected Overrides Function CreateDayCell(ByVal dt As DateTime) As DayNumberCellInfo
        Return New CustomDayNumberCellInfo(dt)
    End Function
    Protected Overrides Function CreateMonthCellInfo(ByVal row As Integer, ByVal col As Integer) As DayNumberCellInfo
        Dim oldInfo As DayNumberCellInfo
        oldInfo = MyBase.CreateMonthCellInfo(row, col)
        If oldInfo Is Nothing Then
            Return oldInfo
        End If
        Dim patchedInfo As New CustomDayNumberCellInfo(oldInfo.Date)
        patchedInfo.Text = oldInfo.Text
        Return patchedInfo
    End Function
    Protected Overrides Function CreateYearCellInfo(ByVal row As Integer, ByVal col As Integer) As DayNumberCellInfo
        Dim oldInfo As DayNumberCellInfo
        oldInfo = MyBase.CreateYearCellInfo(row, col)
        If oldInfo Is Nothing Then
            Return oldInfo
        End If
        Dim patchedInfo As New CustomDayNumberCellInfo(oldInfo.Date)
        patchedInfo.Text = oldInfo.Text
        Return patchedInfo
    End Function
    Public Overrides Function GetHitInfo(ByVal e As MouseEventArgs) As CalendarHitInfo
        Dim baseHitInfo As CalendarHitInfo = MyBase.GetHitInfo(e)
        If baseHitInfo.InfoType <> CalendarHitInfoType.Unknown Then
            Return baseHitInfo
        End If
        If OkButtonRect.Contains(e.Location) Then
            baseHitInfo.InfoType = CalendarHitInfoType.Ok
            baseHitInfo.Bounds = OkButtonRect
        ElseIf CancelButtonRect.Contains(e.Location) Then
            baseHitInfo.InfoType = CalendarHitInfoType.Cancel
            baseHitInfo.Bounds = CancelButtonRect
        End If
        If ShowWeekNumbers Then
            For i As Integer = 0 To WeekCells.Count - 1
                If WeekCells(i).Bounds.Contains(e.Location) Then
                    Dim [date] As New DateTime(DayCells(0).Date.Year, DayCells(0).Date.Month, DayCells(0).Date.Day, 0, 0, 0)
                    [date] = [date].AddDays(7 * i)
                    Dim cell As New DayNumberCellInfo([date])
                    baseHitInfo.InfoType = CalendarHitInfoType.WeekNumber
                    baseHitInfo.HitObject = cell
                End If
            Next i
        End If
        Return baseHitInfo
    End Function
    Protected Overrides Sub CalcHeaderInfo()
        MyBase.CalcHeaderInfo()
        Dim indent As Integer = GetButtonRect(Rectangle.Empty).Width \ 2
        ClearRect = New Rectangle(LeftArrowInfo.Bounds.Right + indent, Content.Bottom + IndentFromDateInfoToClearText, ClearRect.Width, ClearRect.Height)
        OkRect = New Rectangle(LeftArrowInfo.Bounds.Right + (RightArrowInfo.Bounds.X - LeftArrowInfo.Bounds.Right - OkRect.Width) / 2, Content.Bottom + IndentFromDateInfoToClearText, OkRect.Width, OkRect.Height)
        CancelRect = New Rectangle(RightArrowInfo.Bounds.X - indent - CancelRect.Right, Content.Bottom + IndentFromDateInfoToClearText, CancelRect.Width, CancelRect.Height)
        OkButtonRect = GetButtonRect(OkRect)
        CancelButtonRect = GetButtonRect(CancelRect)
        ClearButtonRect = GetButtonRect(ClearRect)
    End Sub
End Class
Public Class VistaDatePeriodEditPainter
    Inherits VistaDateEditPainter
    Public Sub New(ByVal calendar As DateEditCalendarBase)
        MyBase.New(calendar)
    End Sub
    Protected Overrides Sub DrawContent(ByVal info As DevExpress.XtraEditors.Calendar.CalendarObjectInfoArgs)
        MyBase.DrawContent(info)
    End Sub
    Protected Overrides Sub DrawDayCell(ByVal info As CalendarObjectInfoArgs, ByVal cell As DayNumberCellInfo)
        Dim isDrawn As Boolean = False
        Dim patchCell As CustomDayNumberCellInfo = TryCast(cell, CustomDayNumberCellInfo)
        If patchCell IsNot Nothing Then
            isDrawn = DrawPatchedCell(info, patchCell)
        End If
        If (Not isDrawn) Then
            MyBase.DrawDayCell(info, cell)
        End If
    End Sub
    Protected Overridable Function DrawPatchedCell(ByVal info As CalendarObjectInfoArgs, ByVal cell As CustomDayNumberCellInfo) As Boolean
        cell.Today = cell.Marked
        MyBase.DrawDayCell(info, cell)
        If (Not cell.Marked) Then
            If cell.ContainMark Then
                MarkCellContent(info, cell)
            End If
        End If
        Return True
    End Function
    Protected Overrides Sub DrawWeekdaysAbbreviation(ByVal info As CalendarObjectInfoArgs)
        If (CType(info.Calendar, VistaDatePeriodEditCalendar)).ViewLevel = ViewLevel.Weeks Then
            Return
        End If
        MyBase.DrawWeekdaysAbbreviation(info)
    End Sub
    Protected Overridable Sub MarkCellContent(ByVal info As CalendarObjectInfoArgs, ByVal cell As DayNumberCellInfo)
        Dim width As Integer = cell.Bounds.Width \ 3, height As Integer = cell.Bounds.Height \ 3
        Dim r As New Rectangle(cell.Bounds.Location, New Size(width, height))
        r.Offset(width * 2, height * 2)
        Dim icon As New DayNumberCellInfo(cell.Date)
        icon.Today = True
        icon.Bounds = r
        icon.Text = String.Empty
        icon.Selected = True
        MyBase.DrawDayCell(info, icon)
    End Sub
    Protected Overrides Sub DrawHeader(ByVal info As CalendarObjectInfoArgs)
        MyBase.DrawHeader(info)
        Dim vdi As VistaDateEditInfoArgs = TryCast(info, VistaDateEditInfoArgs)
        If vdi Is Nothing Then
            Return
        End If
        DrawOk(vdi)
        DrawCancel(vdi)
    End Sub
End Class
Public Class VistaDatePeriodEditCalendarSelectState
    Inherits VistaDateEditCalendarSelectState
    Public Sub New(ByVal control As DateEditCalendarBase)
        MyBase.New(control)
    End Sub
    Public Overridable ReadOnly Property DatePeriodCalendar() As VistaDatePeriodEditCalendar
        Get
            Return TryCast(VistaCalendar, VistaDatePeriodEditCalendar)
        End Get
    End Property
    Protected Overloads Overrides Sub UpdateSelection(ByVal e As MouseEventArgs)
        If DatePeriodCalendar.Properties.OptionsSelection.MultiselectBehaviour = MultiselectBehaviour.Disabled Then
            Return
        End If
        Dim oldSelectionCount As Integer = DatePeriodCalendar.Selection.Count
        MyBase.UpdateSelection(e)
        If oldSelectionCount <> DatePeriodCalendar.Selection.Count AndAlso DatePeriodCalendar.Selection.Count = 0 Then
            DatePeriodCalendar.UpdateSelection()
        End If
    End Sub
    Protected Overrides ReadOnly Property ShiftKeyPressed() As Boolean
        Get
            Return False
        End Get
    End Property
    Protected Overrides Sub FindMinMaxDateInRect(ByVal rect As Rectangle, ByRef minDate As DateTime, ByRef maxDate As DateTime, ByVal inverse As Boolean)
        Dim down, up As Point
        If inverse Then
            down = New Point(rect.Left, rect.Bottom)
            up = New Point(rect.Right, rect.Top)
        Else
            up = rect.Location
            down = New Point(rect.Right, rect.Bottom)
        End If
        Dim minCell, maxCell As DayNumberCellInfo
        minCell = GetCellByPoint(down, False)
        maxCell = GetCellByPoint(up, False)
        minDate = DateTime.MaxValue
        maxDate = DateTime.MinValue
        If minCell IsNot Nothing AndAlso maxCell IsNot Nothing Then
            If maxCell IsNot minCell Then
                If minCell.Date < maxCell.Date Then
                    minDate = minCell.Date
                    maxDate = maxCell.Date
                Else
                    maxDate = minCell.Date
                    minDate = maxCell.Date
                End If
            End If
        End If
    End Sub
    Protected Overrides Function GetCellByPoint(ByVal pt As Point, ByVal nearestLeft As Boolean) As DayNumberCellInfo
        For Each cell As DayNumberCellInfo In DatePeriodCalendar.GetDayCells()
            If cell.Bounds.Contains(pt) Then
                Return cell
            End If
        Next cell
        Return Nothing
    End Function
End Class
Public Class CustomDayNumberCellInfo
    Inherits DayNumberCellInfo
    Private marked_Renamed As Boolean
    Private containMark_Renamed As Boolean
    Public Sub New(ByVal [date] As DateTime)
        MyBase.New([date])
        marked_Renamed = False
        containMark_Renamed = False
    End Sub
    Public Property Marked() As Boolean
        Get
            Return marked_Renamed
        End Get
        Set(ByVal value As Boolean)
            marked_Renamed = value
        End Set
    End Property
    Public Property ContainMark() As Boolean
        Get
            Return containMark_Renamed
        End Get
        Set(ByVal value As Boolean)
            containMark_Renamed = value
        End Set
    End Property
End Class
<TypeConverter(GetType(ExpandableObjectConverter))> _
Public Class OptionsSelection
    Private multiselectBehaviour_Renamed As MultiselectBehaviour
    Private lowLevel_Renamed, highLevel, defaultLevel_Renamed As ViewLevel
    Private showWeekLevel_Renamed As Boolean
    Public Sub New()
        multiselectBehaviour_Renamed = MultiselectBehaviour.Merging
        lowLevel_Renamed = ViewLevel.Days
        highLevel = ViewLevel.Years
        defaultLevel_Renamed = ViewLevel.Days
        showWeekLevel_Renamed = False
    End Sub
    <Description("Allow chose multiselection behaviour."), Category(CategoryName.Properties), DefaultValue(MultiselectBehaviour.Merging)> _
    Public Property MultiselectBehaviour() As MultiselectBehaviour
        Get
            Return multiselectBehaviour_Renamed
        End Get
        Set(ByVal value As MultiselectBehaviour)
            multiselectBehaviour_Renamed = value
        End Set
    End Property
    <Description("Allow chose weather week level will be shown."), Category(CategoryName.Properties), DefaultValue(False)> _
    Public Property ShowWeekLevel() As Boolean
        Get
            Return showWeekLevel_Renamed
        End Get
        Set(ByVal value As Boolean)
            showWeekLevel_Renamed = value
        End Set
    End Property
    <Description("Allow chose the lowest navigation level."), Category(CategoryName.Properties), DefaultValue(ViewLevel.Days)> _
    Public Property LowLevel() As ViewLevel
        Get
            Return lowLevel_Renamed
        End Get
        Set(ByVal value As ViewLevel)
            lowLevel_Renamed = value
        End Set
    End Property
    <Description("Allow chose the highest navigation level."), Category(CategoryName.Properties), DefaultValue(ViewLevel.Years)> _
    Public Property HightLevel() As ViewLevel
        Get
            Return highLevel
        End Get
        Set(ByVal value As ViewLevel)
            highLevel = value
        End Set
    End Property
    <Description("Allow chose the first shown level."), Category(CategoryName.Properties), DefaultValue(ViewLevel.Days)> _
    Public Property DefaultLevel() As ViewLevel
        Get
            Return defaultLevel_Renamed
        End Get
        Set(ByVal value As ViewLevel)
            defaultLevel_Renamed = value
        End Set
    End Property
End Class
Public Enum MultiselectBehaviour
    Merging
    Intersection
    Disabled
End Enum
Public Enum ViewLevel
    Days
    Weeks
    Months
    Years
End Enum
Public Enum StoreMode
    [Default]
    PeriodsSet
    [String]
End Enum
Public Class Period
    Implements IComparable
    Private begin_Renamed, end_Renamed As DateTime
    Public Sub New(ByVal begin As DateTime, ByVal [end] As DateTime)
        Me.begin_Renamed = begin.Date
        Me.end_Renamed = EndOfDay([end])
    End Sub
    Public Sub New(ByVal [date] As DateTime)
        Me.New([date], [date])
    End Sub
    Public Shared Function EndOfDay(ByVal [date] As DateTime) As DateTime
        Return [date].Date.AddDays(1).AddSeconds(-1)
    End Function
    Public Shared Function BeginOfDay(ByVal [date] As DateTime) As DateTime
        Return [date].Date
    End Function
    Public Property Begin() As DateTime
        Get
            Return begin_Renamed
        End Get
        Set(ByVal value As DateTime)
            If Begin <> value Then
                begin_Renamed = value.Date
            End If
        End Set
    End Property
    Public Property [End]() As DateTime
        Get
            Return end_Renamed
        End Get
        Set(ByVal value As DateTime)
            If [End] <> value Then
                end_Renamed = EndOfDay(value)
            End If
        End Set
    End Property
    Public Function CompareTo(ByVal obj As Object) As Integer Implements IComparable.CompareTo
        Dim dp As Period = TryCast(obj, Period)
        If dp IsNot Nothing Then
            Return Me.Begin.CompareTo(dp.Begin)
        Else
            Throw New ArgumentException("Object is not a DatePeriod")
        End If
    End Function
    Public Overrides Function ToString() As String
        If Begin.Date = [End].Date Then
            Return Begin.ToString("d")
        End If
        Return Begin.ToString("d") & " - " & [End].ToString("d")
    End Function
    Public Overridable Overloads Function ToString(ByVal formatString As String) As String
        If formatString = String.Empty Then
            Return ToString()
        End If
        If Begin.Date = [End].Date Then
            Return Begin.ToString(formatString)
        End If
        Return Begin.ToString(formatString) & " - " & [End].ToString(formatString)
    End Function
    Public Overridable Overloads Function ToString(ByVal format As IFormatProvider) As String
        If format Is Nothing Then
            Return ToString()
        End If
        If Begin.Date = [End].Date Then
            Return Begin.ToString(format)
        End If
        Return Begin.ToString(format) & " - " & [End].ToString(format)
    End Function
    Public Shared Function Parse(ByVal str As String, ByVal format As IFormatProvider) As Period
        str = str.Trim()
        If str.Contains(" - ") Then
            Dim success As Boolean = True
            Dim periodSeparators(0) As String
            periodSeparators(0) = " - "
            Dim sides() As String = String.Format("{0}", str).Split(periodSeparators, StringSplitOptions.RemoveEmptyEntries)
            Dim dates(1) As DateTime
            Dim i As Integer = 0
            For Each dateStr As String In sides
                If i > 1 Then
                    Continue For
                End If
                Dim stringDate As String = dateStr.Trim()
                success = success AndAlso DateTime.TryParse(stringDate, format, DateTimeStyles.None, dates(i))
                i += 1
            Next dateStr
            If success Then
                If dates(0) <= dates(1) Then
                    Return New Period(dates(0), dates(1))
                End If
            End If
        Else
            Dim dt As DateTime
            If DateTime.TryParse(str, format, DateTimeStyles.None, dt) Then
                Return New Period(dt)
            End If
        End If
        Return Nothing
    End Function
End Class
Public Class PeriodsSet
    Private periods_Renamed As ArrayList
    Protected Shared ReadOnly Property DefaultSeparator() As Char
        Get
            Return ","c
        End Get
    End Property
    Protected Shared ReadOnly Property InvariantCulture() As CultureInfo
        Get
            Return New CultureInfo(String.Empty)
        End Get
    End Property
    Public Sub New()
        periods_Renamed = New ArrayList()
    End Sub
    Default Public Property Item(ByVal index As Integer) As Period
        Get
            Return TryCast(periods_Renamed(index), Period)
        End Get
        Set(ByVal value As Period)
            periods_Renamed(index) = value
        End Set
    End Property
    Protected Overridable Function Add(ByVal value As Period) As Integer
        For Each dp As Period In periods_Renamed
            If dp.Begin.Date = value.End.Date.AddDays(1) Then
                dp.Begin = value.Begin
                Return periods_Renamed.IndexOf(dp)
            End If
            If dp.End.Date = value.Begin.Date.AddDays(-1) Then
                dp.End = value.End
                Return periods_Renamed.IndexOf(dp)
            End If
        Next dp
        periods_Renamed.Add(value)
        periods_Renamed.Sort()
        Return periods_Renamed.IndexOf(value)
    End Function
    Public ReadOnly Property Periods() As ArrayList
        Get
            Return periods_Renamed
        End Get
    End Property
    Public Sub IntersectWith(ByVal begin As DateTime, ByVal [end] As DateTime)
        If begin.Date > [end].Date Then
            Return
        End If
        begin = Period.BeginOfDay(begin)
        [end] = Period.EndOfDay([end])
        Dim i As Integer = 0
        Do While i < Periods.Count
            If begin <= Me(i).Begin AndAlso [end] >= Me(i).End Then
                Dim oldBegin As DateTime = Me(i).Begin, oldEnd As DateTime = Me(i).End
                periods_Renamed.RemoveAt(i)
                IntersectWith(begin, oldBegin.AddSeconds(-1))
                IntersectWith(oldEnd.AddSeconds(1), [end])
                Return
            End If
            i += 1
        Loop
        For Each dp As Period In periods_Renamed
            If begin > dp.Begin AndAlso [end] < dp.End Then
                Dim periodEnd As DateTime = dp.End
                dp.End = begin.AddSeconds(-1)
                IntersectWith([end].AddSeconds(1), periodEnd)
                Return
            End If
        Next dp
        For i_1 As Integer = 0 To Periods.Count - 1
            If begin = Me(i_1).Begin Then
                Me(i_1).Begin = [end].AddSeconds(1)
                Return
            End If
            If [end] = Me(i_1).End Then
                Me(i_1).End = begin.AddSeconds(-1)
                Return
            End If
        Next i_1
        For i_2 As Integer = 0 To Periods.Count - 1
            If begin >= Me(i_2).Begin AndAlso begin <= Me(i_2).End Then
                Dim oldEnd As DateTime = Me(i_2).End
                Me(i_2).End = begin.AddSeconds(-1)
                begin = oldEnd.AddSeconds(1)
            End If
            If [end] >= Me(i_2).Begin AndAlso [end] <= Me(i_2).End Then
                Dim oldBegin As DateTime = Me(i_2).Begin
                Me(i_2).Begin = [end].AddSeconds(1)
                [end] = oldBegin.AddSeconds(-1)
            End If
        Next i_2
        Add(New Period(begin, [end]))
    End Sub
    Public Sub MergeWith(ByVal begin As DateTime, ByVal [end] As DateTime)
        If begin.Date > [end].Date Then
            Return
        End If
        begin = Period.BeginOfDay(begin)
        [end] = Period.EndOfDay([end])
        If ContainPeriod(begin, [end]) Then
            Return
        End If
        For i As Integer = 0 To Periods.Count - 1
            If begin <= Me(i).Begin AndAlso [end] >= Me(i).End Then
                periods_Renamed.RemoveAt(i)
                MergeWith(begin, [end])
                Return
            End If
        Next i
        Dim beginPeriod As Period = Nothing, endPeriod As Period = Nothing
        For i_1 As Integer = 0 To Periods.Count - 1
            If begin >= Me(i_1).Begin AndAlso begin <= Me(i_1).End Then
                beginPeriod = Me(i_1)
            End If
            If [end] >= Me(i_1).Begin AndAlso [end] <= Me(i_1).End Then
                endPeriod = Me(i_1)
            End If
        Next i_1
        If beginPeriod IsNot Nothing AndAlso endPeriod IsNot Nothing Then
            beginPeriod.End = endPeriod.End
            periods_Renamed.Remove(endPeriod)
            Return
        End If
        If beginPeriod IsNot Nothing Then
            beginPeriod.End = [end]
            Return
        End If
        If endPeriod IsNot Nothing Then
            endPeriod.Begin = begin
            Return
        End If
        Add(New Period(begin, [end]))
    End Sub
    Public Function ContainPeriod(ByVal item As Object) As Boolean
        Dim dp As Period = TryCast(item, Period)
        If dp IsNot Nothing Then
            Return ContainPeriod(dp.Begin, dp.End)
        End If
        Return False
    End Function
    Public Overridable Function ContainPeriod(ByVal begin As DateTime, ByVal [end] As DateTime) As Boolean
        For i As Integer = 0 To Periods.Count - 1
            If begin >= Me(i).Begin AndAlso [end] <= Me(i).End Then
                Return True
            End If
        Next i
        Return False
    End Function
    Public Overridable Function ContainPartOfPeriod(ByVal begin As DateTime, ByVal [end] As DateTime) As Boolean
        If ContainPeriod(begin, [end]) Then
            Return True
        End If
        For i As Integer = 0 To Periods.Count - 1
            If (begin <= Me(i).Begin AndAlso [end] >= Me(i).Begin) OrElse (begin <= Me(i).End AndAlso [end] >= Me(i).End) Then
                Return True
            End If
        Next i
        Return False
    End Function
    Public Overridable Function GetCopy() As PeriodsSet
        Dim result As New PeriodsSet()
        For Each period As Period In periods_Renamed
            result.Add(period)
        Next period
        Return result
    End Function
    Public Overridable Overloads Function ToString(ByVal format As IFormatProvider, ByVal separator As Char) As String
        Dim str As String = String.Empty
        For Each dp As Period In periods_Renamed
            str = str & dp.ToString(format) + separator.ToString() & " "
        Next dp
        If str.Length > 2 Then
            str = str.Remove(str.Length - 2)
        End If
        Return str
    End Function
    Public Overridable Overloads Function ToString(ByVal formatString As String, ByVal separator As Char) As String
        Dim str As String = String.Empty
        For Each dp As Period In periods_Renamed
            str = str & dp.ToString(formatString) + separator.ToString() & " "
        Next dp
        If str.Length > 2 Then
            str = str.Remove(str.Length - 2)
        End If
        Return str
    End Function
    Public Overrides Function ToString() As String
        Return ToString(InvariantCulture, DefaultSeparator)
    End Function
    Public Shared Function Parse(ByVal str As String) As PeriodsSet
        Return Parse(str, InvariantCulture, DefaultSeparator)
    End Function
    Public Shared Function Parse(ByVal str As String, ByVal format As IFormatProvider, ByVal separatorChar As Char) As PeriodsSet
        Dim result As New PeriodsSet()
        Dim periodSet() As String = String.Format("{0}", str).Split(separatorChar)
        For Each periodStr As String In periodSet
            Dim dp As Period = Period.Parse(periodStr, format)
            If dp IsNot Nothing Then
                result.Add(dp)
            End If
        Next periodStr
        Return result
    End Function
End Class