How to assign typical NumericUpDown properties to custom NumericUpDown based control? - vb.net

Question

I'm trying to make a DataGridViewColumn that inherits all of the properties of a typical NumericUpDown control. I found an answer here on StackOverflow (https://stackoverflow.com/a/55788490/692250) and a MSDN article here (https://learn.microsoft.com/en-us/dotnet/desktop/winforms/controls/how-to-host-controls-in-windows-forms-datagridview-cells?view=netframeworkdesktop-4.8&redirectedfrom=MSDN#code-snippet-1).
The code from the article works well, but... I cannot assign a Maximum nor Minimum value to the control (both are stuck at the "default" Minimum of 0 and Maximum of 100).
I tried to add in code from the SO answer (by adding in a Min and Max field) but doing so locks both in to 0 and unable to change.
The question in short: how do I add the necessary properties to allow to this work.
The custom control is question:
Public Class NumericUpDownColumn
Inherits DataGridViewColumn
Public Sub New()
MyBase.New(New NumericUpDownCell())
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 Not (value Is Nothing) AndAlso Not value.GetType().IsAssignableFrom(GetType(NumericUpDownCell)) Then
Throw New InvalidCastException("Must be an Integer")
End If
MyBase.CellTemplate = value
End Set
End Property
End Class
Public Class NumericUpDownCell
Inherits DataGridViewTextBoxCell
Public Sub New()
' Number Format
Me.Style.Format = "0"
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 NumericUpDownEditingControl = CType(DataGridView.EditingControl, NumericUpDownEditingControl)
ctl.Value = CType(Me.Value, Decimal)
End Sub
Public Overrides ReadOnly Property EditType() As Type
Get
' Return the type of the editing contol that CalendarCell uses.
Return GetType(NumericUpDownEditingControl)
End Get
End Property
Public Overrides ReadOnly Property ValueType() As Type
Get
' Return the type of the value that CalendarCell contains.
Return GetType(Decimal)
End Get
End Property
Public Overrides ReadOnly Property DefaultNewRowValue() As Object
Get
' Use the current date and time as the default value.
Return 0
End Get
End Property
End Class
Class NumericUpDownEditingControl
Inherits NumericUpDown
Implements IDataGridViewEditingControl
Private dataGridViewControl As DataGridView
Private valueIsChanged As Boolean = False
Private rowIndexNum As Integer
Public Sub New()
Me.DecimalPlaces = 0
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 Decimal Then
Me.Value = Decimal.Parse(value.ToString)
End If
End Set
End Property
Public Function GetEditingControlFormattedValue(ByVal context As DataGridViewDataErrorContexts) As Object Implements IDataGridViewEditingControl.GetEditingControlFormattedValue
Return Me.Value.ToString("#")
End Function
Public Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As DataGridViewCellStyle) Implements IDataGridViewEditingControl.ApplyCellStyleToEditingControl
Me.Font = dataGridViewCellStyle.Font
Me.ForeColor = dataGridViewCellStyle.ForeColor
Me.BackColor = 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
Focusing on it a bit more, I found that I can assign values to the Maximum and Minimum fields as so:
' Set the value of the editing control to the current cell value.
MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle)
Dim ctl As NumericUpDownEditingControl = CType(DataGridView.EditingControl, NumericUpDownEditingControl)
ctl.Value = CType(Me.Value, Decimal)
ctl.Maximum = 180
ctl.Minimum = -1
End Sub
But I cannot seem to pass to this field via the usual means of .Maximum or .Minimum on the constructor. Any tips/advice?

Answer 1

This is an easy fix and very easy to overlook.
In your NumericUpDownCell class you need to override the Clone method to include the new Minimum and Maximum properties, for example:
First, add the new properties the NumericUpDownCell class and then override the Clone function
Public Class NumericUpDownCell
Inherits DataGridViewTextBoxCell
...
Public Property Minimum() As Integer
Public Property Maximum() As Integer
...
Public Overrides Function Clone() As Object
Dim retVal As NumericUpDownCell = CType(MyBase.Clone, NumericUpDownCell)
retVal.Minimum = Me.Minimum
retVal.Maximum = Me.Maximum
Return retVal
End Function
End Class
Second, inside the NumericUpDownCell classes InitializeEditingControl method, add the two lines:
ctl.Minimum = Me.Minimum
ctl.Maximum = Me.Maximum
When you setup the new column, get the CellTemplate to set the new properties, as per:
Dim upDownColumn As New NumericUpDownColumn
Dim cellTemplate As NumericUpDownCell = CType(upDownColumn .CellTemplate, NumericUpDownCell)
cellTemplate.Minimum = 10
cellTemplate.Maximum = 15
Or, following you preference to setup via the constructor, add a new constructor to the NumericUpdDownColumn class as per
Public Sub New(minValue As Integer, maxValue As Integer)
MyBase.New(New NumericUpDownCell())
Dim template As NumericUpDownCell = CType(CellTemplate, NumericUpDownCell)
template.Minimum = minValue
template.Maximum = maxValue
End Sub
and then use it like:
Dim upDownColumn As New NumericUpDownColumn(100, 150)
Dim cellTemplate As NumericUpDownCell = CType(upDownColumn.CellTemplate, NumericUpDownCell)
DataGridView1.Columns.Add(upDownColumn)