How to: Host Controls in Windows Forms DataGridView Cells
The DataGridView control provides several column types, enabling your users to enter and edit values in a variety of ways. If these column types do not meet your data-entry needs, however, you can create your own column types with cells that host controls of your choosing. To do this, you must define classes that derive from DataGridViewColumn and DataGridViewCell. You must also define a class that derives from Control and implements the IDataGridViewEditingControl interface.
The following code example shows how to create a calendar column. The cells of this column display dates in ordinary text box cells, but when the user edits a cell, a DateTimePicker control appears. In order to avoid having to implement text box display functionality again, the CalendarCell class derives from the DataGridViewTextBoxCell class rather than inheriting the DataGridViewCell class directly.
Note
When you derive from DataGridViewCell or DataGridViewColumn and add new properties to the derived class, be sure to override the Clone method to copy the new properties during cloning operations. You should also call the base class's Clone method so that the properties of the base class are copied to the new cell or column.
Example
Imports System
Imports System.Windows.Forms
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 = "d"
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)
' Use the default row value when Value property is null.
If (Me.Value Is Nothing) Then
ctl.Value = CType(Me.DefaultNewRowValue, DateTime)
Else
ctl.Value = CType(Me.Value, DateTime)
End If
End Sub
Public Overrides ReadOnly Property EditType() As Type
Get
' Return the type of the editing control 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.Short
End Sub
Public Property EditingControlFormattedValue() As Object _
Implements IDataGridViewEditingControl.EditingControlFormattedValue
Get
Return Me.Value.ToShortDateString()
End Get
Set(ByVal value As Object)
Try
' This will throw an exception of the string is
' null, empty, or not in the format of a date.
Me.Value = DateTime.Parse(CStr(value))
Catch
' In the case of an exception, just use the default
' value so we're not left with a null value.
Me.Value = DateTime.Now
End Try
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 Not dataGridViewWantsInputKey
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
Public Class Form1
Inherits Form
Private dataGridView1 As New DataGridView()
<STAThreadAttribute()> _
Public Shared Sub Main()
Application.Run(New Form1())
End Sub
Public Sub New()
Me.dataGridView1.Dock = DockStyle.Fill
Me.Controls.Add(Me.dataGridView1)
Me.Text = "DataGridView calendar column demo"
End Sub
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
Handles Me.Load
Dim col As New CalendarColumn()
Me.dataGridView1.Columns.Add(col)
Me.dataGridView1.RowCount = 5
Dim row As DataGridViewRow
For Each row In Me.dataGridView1.Rows
row.Cells(0).Value = DateTime.Now
Next row
End Sub
End Class
using System;
using System.Windows.Forms;
public class CalendarColumn : DataGridViewColumn
{
public CalendarColumn() : base(new CalendarCell())
{
}
public override DataGridViewCell CellTemplate
{
get
{
return base.CellTemplate;
}
set
{
// Ensure that the cell used for the template is a CalendarCell.
if (value != null &&
!value.GetType().IsAssignableFrom(typeof(CalendarCell)))
{
throw new InvalidCastException("Must be a CalendarCell");
}
base.CellTemplate = value;
}
}
}
public class CalendarCell : DataGridViewTextBoxCell
{
public CalendarCell()
: base()
{
// Use the short date format.
this.Style.Format = "d";
}
public override void InitializeEditingControl(int rowIndex, object
initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
{
// Set the value of the editing control to the current cell value.
base.InitializeEditingControl(rowIndex, initialFormattedValue,
dataGridViewCellStyle);
CalendarEditingControl ctl =
DataGridView.EditingControl as CalendarEditingControl;
// Use the default row value when Value property is null.
if (this.Value == null)
{
ctl.Value = (DateTime)this.DefaultNewRowValue;
}
else
{
ctl.Value = (DateTime)this.Value;
}
}
public override Type EditType
{
get
{
// Return the type of the editing control that CalendarCell uses.
return typeof(CalendarEditingControl);
}
}
public override Type ValueType
{
get
{
// Return the type of the value that CalendarCell contains.
return typeof(DateTime);
}
}
public override object DefaultNewRowValue
{
get
{
// Use the current date and time as the default value.
return DateTime.Now;
}
}
}
class CalendarEditingControl : DateTimePicker, IDataGridViewEditingControl
{
DataGridView dataGridView;
private bool valueChanged = false;
int rowIndex;
public CalendarEditingControl()
{
this.Format = DateTimePickerFormat.Short;
}
// Implements the IDataGridViewEditingControl.EditingControlFormattedValue
// property.
public object EditingControlFormattedValue
{
get
{
return this.Value.ToShortDateString();
}
set
{
if (value is String)
{
try
{
// This will throw an exception of the string is
// null, empty, or not in the format of a date.
this.Value = DateTime.Parse((String)value);
}
catch
{
// In the case of an exception, just use the
// default value so we're not left with a null
// value.
this.Value = DateTime.Now;
}
}
}
}
// Implements the
// IDataGridViewEditingControl.GetEditingControlFormattedValue method.
public object GetEditingControlFormattedValue(
DataGridViewDataErrorContexts context)
{
return EditingControlFormattedValue;
}
// Implements the
// IDataGridViewEditingControl.ApplyCellStyleToEditingControl method.
public void ApplyCellStyleToEditingControl(
DataGridViewCellStyle dataGridViewCellStyle)
{
this.Font = dataGridViewCellStyle.Font;
this.CalendarForeColor = dataGridViewCellStyle.ForeColor;
this.CalendarMonthBackground = dataGridViewCellStyle.BackColor;
}
// Implements the IDataGridViewEditingControl.EditingControlRowIndex
// property.
public int EditingControlRowIndex
{
get
{
return rowIndex;
}
set
{
rowIndex = value;
}
}
// Implements the IDataGridViewEditingControl.EditingControlWantsInputKey
// method.
public bool EditingControlWantsInputKey(
Keys key, bool dataGridViewWantsInputKey)
{
// Let the DateTimePicker handle the keys listed.
switch (key & Keys.KeyCode)
{
case Keys.Left:
case Keys.Up:
case Keys.Down:
case Keys.Right:
case Keys.Home:
case Keys.End:
case Keys.PageDown:
case Keys.PageUp:
return true;
default:
return !dataGridViewWantsInputKey;
}
}
// Implements the IDataGridViewEditingControl.PrepareEditingControlForEdit
// method.
public void PrepareEditingControlForEdit(bool selectAll)
{
// No preparation needs to be done.
}
// Implements the IDataGridViewEditingControl
// .RepositionEditingControlOnValueChange property.
public bool RepositionEditingControlOnValueChange
{
get
{
return false;
}
}
// Implements the IDataGridViewEditingControl
// .EditingControlDataGridView property.
public DataGridView EditingControlDataGridView
{
get
{
return dataGridView;
}
set
{
dataGridView = value;
}
}
// Implements the IDataGridViewEditingControl
// .EditingControlValueChanged property.
public bool EditingControlValueChanged
{
get
{
return valueChanged;
}
set
{
valueChanged = value;
}
}
// Implements the IDataGridViewEditingControl
// .EditingPanelCursor property.
public Cursor EditingPanelCursor
{
get
{
return base.Cursor;
}
}
protected override void OnValueChanged(EventArgs eventargs)
{
// Notify the DataGridView that the contents of the cell
// have changed.
valueChanged = true;
this.EditingControlDataGridView.NotifyCurrentCellDirty(true);
base.OnValueChanged(eventargs);
}
}
public class Form1 : Form
{
private DataGridView dataGridView1 = new DataGridView();
[STAThreadAttribute()]
public static void Main()
{
Application.Run(new Form1());
}
public Form1()
{
this.dataGridView1.Dock = DockStyle.Fill;
this.Controls.Add(this.dataGridView1);
this.Load += new EventHandler(Form1_Load);
this.Text = "DataGridView calendar column demo";
}
private void Form1_Load(object sender, EventArgs e)
{
CalendarColumn col = new CalendarColumn();
this.dataGridView1.Columns.Add(col);
this.dataGridView1.RowCount = 5;
foreach (DataGridViewRow row in this.dataGridView1.Rows)
{
row.Cells[0].Value = DateTime.Now;
}
}
}
Compiling the Code
The following example requires:
- References to the System and System.Windows.Forms assemblies.
For information about building this example from the command line for Visual Basic or Visual C#, see Building from the Command Line (Visual Basic) or Command-line Building With csc.exe. You can also build this example in Visual Studio by pasting the code into a new project. How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
See Also
Concepts
DataGridView Control Architecture (Windows Forms)
Column Types in the Windows Forms DataGridView Control