Public Class CalendarColumn
    Inherits DataGridViewColumn
    Public Sub New()
        MyBase.New(New CalendarCell())
    End Sub
    Public Overrides Property CellTemplate() As DataGridViewCell
        Get
            Return MyBase.CellTemplate
        End Get
        Set(ByVal value As DataGridViewCell)
            ' Ensure that the cell used for the template is a CalendarCell.
            If (value IsNot Nothing) AndAlso _
                Not value.GetType().IsAssignableFrom(GetType(CalendarCell)) _
                Then
                Throw New InvalidCastException("Must be a CalendarCell")
            End If
            MyBase.CellTemplate = value
        End Set
    End Property
End Class
Public Class CalendarCell
    Inherits DataGridViewTextBoxCell
    Public Sub New()
        ' Use the short date format.
        Me.Style.Format = "MM/dd hh:mm tt"
    End Sub
    Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, _
        ByVal initialFormattedValue As Object, _
        ByVal dataGridViewCellStyle As DataGridViewCellStyle)
        ' Set the value of the editing control to the current cell value.
        MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, _
            dataGridViewCellStyle)
        Dim ctl As CalendarEditingControl = _
            CType(DataGridView.EditingControl, CalendarEditingControl)
        ctl.Value = CType(Me.Value, DateTime)
    End Sub
    Public Overrides ReadOnly Property EditType() As Type
        Get
            ' Return the type of the editing contol that CalendarCell uses.
            Return GetType(CalendarEditingControl)
        End Get
    End Property
    Public Overrides ReadOnly Property ValueType() As Type
        Get
            ' Return the type of the value that CalendarCell contains.
            Return GetType(DateTime)
        End Get
    End Property
    Public Overrides ReadOnly Property DefaultNewRowValue() As Object
        Get
            ' Use the current date and time as the default value.
            Return DateTime.Now
        End Get
    End Property
End Class
Class CalendarEditingControl
    Inherits DateTimePicker
    Implements IDataGridViewEditingControl
    Private dataGridViewControl As DataGridView
    Private valueIsChanged As Boolean = False
    Private rowIndexNum As Integer
    Public Sub New()
        Me.Format = DateTimePickerFormat.Custom
        Me.CustomFormat = "MM/dd hh:mm tt"
        Me.ShowUpDown = True
    End Sub
    Public Property EditingControlFormattedValue() As Object _
        Implements IDataGridViewEditingControl.EditingControlFormattedValue
        Get
            Return Me.Value.ToString
        End Get
        Set(ByVal value As Object)
            If TypeOf value Is String Then
                Me.Value = DateTime.Parse(CStr(value))
            End If
        End Set
    End Property
    Public Function GetEditingControlFormattedValue(ByVal context _
        As DataGridViewDataErrorContexts) As Object _
        Implements IDataGridViewEditingControl.GetEditingControlFormattedValue
        Return Me.Value.ToShortDateString
    End Function
    Public Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As _
        DataGridViewCellStyle) _
        Implements IDataGridViewEditingControl.ApplyCellStyleToEditingControl
        Me.Font = dataGridViewCellStyle.Font
        Me.CalendarForeColor = dataGridViewCellStyle.ForeColor
        Me.CalendarMonthBackground = dataGridViewCellStyle.BackColor
    End Sub
    Public Property EditingControlRowIndex() As Integer _
        Implements IDataGridViewEditingControl.EditingControlRowIndex
        Get
            Return rowIndexNum
        End Get
        Set(ByVal value As Integer)
            rowIndexNum = value
        End Set
    End Property
    Public Function EditingControlWantsInputKey(ByVal key As Keys, _
        ByVal dataGridViewWantsInputKey As Boolean) As Boolean _
        Implements IDataGridViewEditingControl.EditingControlWantsInputKey
        ' Let the DateTimePicker handle the keys listed.
        Select Case key And Keys.KeyCode
            Case Keys.Left, Keys.Up, Keys.Down, Keys.Right, _
                Keys.Home, Keys.End, Keys.PageDown, Keys.PageUp
                Return True
            Case Else
                Return False
        End Select
    End Function
    Public Sub PrepareEditingControlForEdit(ByVal selectAll As Boolean) _
        Implements IDataGridViewEditingControl.PrepareEditingControlForEdit
        ' No preparation needs to be done.
    End Sub
    Public ReadOnly Property RepositionEditingControlOnValueChange() _
        As Boolean Implements _
        IDataGridViewEditingControl.RepositionEditingControlOnValueChange
        Get
            Return False
        End Get
    End Property
    Public Property EditingControlDataGridView() As DataGridView _
        Implements IDataGridViewEditingControl.EditingControlDataGridView
        Get
            Return dataGridViewControl
        End Get
        Set(ByVal value As DataGridView)
            dataGridViewControl = value
        End Set
    End Property
    Public Property EditingControlValueChanged() As Boolean _
        Implements IDataGridViewEditingControl.EditingControlValueChanged
        Get
            Return valueIsChanged
        End Get
        Set(ByVal value As Boolean)
            valueIsChanged = value
        End Set
    End Property
    Public ReadOnly Property EditingControlCursor() As Cursor _
        Implements IDataGridViewEditingControl.EditingPanelCursor
        Get
            Return MyBase.Cursor
        End Get
    End Property
    Protected Overrides Sub OnValueChanged(ByVal eventargs As EventArgs)
        ' Notify the DataGridView that the contents of the cell have changed.
        valueIsChanged = True
        Me.EditingControlDataGridView.NotifyCurrentCellDirty(True)
        MyBase.OnValueChanged(eventargs)
    End Sub
End Class