Hi,
I'm trying to render a checkbox in a datagridview column header so that when the checkbox is checked/unchecked all the cells in that column should be checked/unchecked accordingly. The datagridview is bound to a database table but the column containing the checkbox header cell is unbound. The problem is, whenever i click the header checkbox, all the cells in that column are checked but the header checkbox itself gets invisible.
If I click the HEADER (though the checkbox is invisible, still I can click the header) again, all the cells in the column below are unchecked and the header checkbox becomes visible and unchecked. Everything is happening as expected except the visibility of the header checkbox. Why is it so? Please suggest how to get rid of it. Regards.
My code follows below:
''' <summary>
''' The custom class for checkbox header cell.
''' </summary>
Imports System.Drawing
Public Delegate Sub CheckBoxClickedHandler(ByVal state As Boolean)
Public Class DataGridViewCheckBoxHeaderCellEventArgs
Inherits EventArgs
Private _bChecked As Boolean
Public Sub New(ByVal bChecked As Boolean)
_bChecked = bChecked
End Sub
Public ReadOnly Property Checked As Boolean
Get
Return _bChecked
End Get
End Property
End Class
Public Class DataGridViewCheckBoxHeaderCell
Inherits DataGridViewColumnHeaderCell
Private checkBoxLocation As Point
Private checkBoxSize As Size
Private _checked As Boolean = False
Private _cellLocation As New Point
Private _cbState As Windows.Forms.VisualStyles.CheckBoxState = VisualStyles.CheckBoxState.UncheckedNormal
Public Event OnCheckBoxClicked As CheckBoxClickedHandler
Public Sub New()
End Sub
Protected Overrides Sub Paint(ByVal graphics As System.Drawing.Graphics, ByVal clipBounds As System.Drawing.Rectangle, ByVal cellBounds As System.Drawing.Rectangle, ByVal rowIndex As Integer, ByVal dataGridViewElementState As System.Windows.Forms.DataGridViewElementStates, ByVal value As Object, ByVal formattedValue As Object, ByVal errorText As String, ByVal cellStyle As System.Windows.Forms.DataGridViewCellStyle, ByVal advancedBorderStyle As System.Windows.Forms.DataGridViewAdvancedBorderStyle, ByVal paintParts As System.Windows.Forms.DataGridViewPaintParts)
MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, dataGridViewElementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts)
Dim p As New Point
Dim s As Size = CheckBoxRenderer.GetGlyphSize(graphics, Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal)
p.X = cellBounds.Location.X + (cellBounds.Width / 2) - (s.Width / 2)
p.Y = cellBounds.Location.Y + (cellBounds.Height / 2) - (s.Height / 2)
_cellLocation = cellBounds.Location
checkBoxLocation = p
checkBoxSize = s
If _checked Then
_cbState = Windows.Forms.VisualStyles.CheckBoxState.CheckedNormal
Else
_cbState = Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal
CheckBoxRenderer.DrawCheckBox(graphics, checkBoxLocation, _cbState)
End If
End Sub
Protected Overrides Sub OnMouseClick(ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs)
Dim p As New Point(e.X + _cellLocation.X, e.Y + _cellLocation.Y)
If p.X >= checkBoxLocation.X And p.X <= checkBoxLocation.X + checkBoxSize.Width And p.Y >= checkBoxLocation.Y And p.Y <= checkBoxLocation.Y + checkBoxSize.Height Then
_checked = Not _checked
RaiseEvent OnCheckBoxClicked(_checked)
Me.DataGridView.InvalidateCell(Me)
End If
MyBase.OnMouseClick(e)
End Sub
End Class
''' <summary>
''' Actual class where the custom class is used.
''' dgvContacts is the name of the datagridview.
''' colCheck is the name of the column containing the checkbox header cell.
''' </summary>
Public Class ContactList
'Other declarations...
......................
......................
Private WithEvents _cbHeader As DataGridViewCheckBoxHeaderCell
Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
_cbHeader = New DataGridViewCheckBoxHeaderCell
colCheck.HeaderCell = _cbHeader
colCheck.HeaderText = ""
colCheck.Visible = True
End Sub
'Other definitions...
.....................
.....................
Private Sub _cbHeader_OnCheckBoxClicked(ByVal state As Boolean) Handles _cbHeader.OnCheckBoxClicked
For i As Integer = 0 To dgvContacts.RowCount - 1
dgvContacts("colCheck", i).Value = state
Next
dgvContacts.EndEdit()
End Sub
End Class