Level: Beginner
Knowledge Required:- DataGridView Control
- Data Binding
Description:
In this post we shall see that how we can transform DataGridView control’s CheckBox column into Radio Button (option button).
I have done 2 main things,
- Created a back-end logic when user clicks on CheckBox Column so only one CheckBox should be checked at a time
- Change the look of CheckBox column so it looks a Radio Button Column
So to understand the first one, consider a DataGridView control as shown in the above figure. This DataGridView control is actually bind with a DataSet for example,
As you can see there are 2 columns. The
IsSelected column is actually a Boolean column which is normally rendered as CheckBox in DataGridView control. What we will be doing is that we first set our DataGridView to
Read Only i.e.,
AllowUserToAddRows = False
AllowUserToDeleteRows = False
ReadOnly = True
We are making our DataGridView control Read Only because it is easier to set the CheckBox checked or unchecked programmatically otherwise DataGridView control itself will be interfering and will create problems and complexities for us.
OK now whenever user clicks on CheckBox we will be performing our custom operation. To do this we will use the DataGridView’s
CellContentClick event. Here is the code,
Private Sub ShutDownOptionsDataGridView_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles ShutDownOptionsDataGridView.CellContentClick
If e.ColumnIndex = Me.columnIsSelected.Index Then
Dim drv As DataRowView
Dim rowShutDownOption As ShutdownOptionDataSet.ShutDownOptionsRow
' in this event handler we know that which DataGridView's row is clicked
' so we are going to extract out the actual DataTable's row which is
' bind with this DataGridView's Row
drv = CType(Me.ShutDownOptionsDataGridView.Rows(e.RowIndex).DataBoundItem, DataRowView)
' get the DataTable's row
rowShutDownOption = CType(drv.Row, ShutdownOptionDataSet.ShutDownOptionsRow)
' get the row which is currently selected
Dim rowCurrentlySelected() As ShutdownOptionDataSet.ShutDownOptionsRow
rowCurrentlySelected = Me.ShutdownOptionDataSet.ShutDownOptions.Select("IsSelected=True")
' if some row found then make it de-selected
If rowCurrentlySelected.Length > 0 Then
rowCurrentlySelected(0).IsSelected = False
End If
' ok now select the row which is clicked
rowShutDownOption.IsSelected = True
End If
End Sub
What we do is first get the row in which
IsSelected=True and we make that row
IsSelected=False. Then we set the row which is clicked as
IsSelected=True.
Next thing is to change the look of CheckBox to OptionButton / RadioButton. For this purpose we will be using DataGridView’s
CellPainting event. Here is the code,
Private Sub ShutDownOptionsDataGridView_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles ShutDownOptionsDataGridView.CellPainting
If e.ColumnIndex = Me.columnIsSelected.Index AndAlso _
e.RowIndex >= 0 Then
e.PaintBackground(e.ClipBounds, True)
Dim rectRadioButton As Rectangle
rectRadioButton.Width = 14
rectRadioButton.Height = 14
rectRadioButton.X = e.CellBounds.X + (e.CellBounds.Width - rectRadioButton.Width) / 2
rectRadioButton.Y = e.CellBounds.Y + (e.CellBounds.Height - rectRadioButton.Height) / 2
If IsDBNull(e.Value) OrElse e.Value = False Then
ControlPaint.DrawRadioButton(e.Graphics, rectRadioButton, ButtonState.Normal)
Else
ControlPaint.DrawRadioButton(e.Graphics, rectRadioButton, ButtonState.Checked)
End If
e.Paint(e.ClipBounds, DataGridViewPaintParts.Focus)
e.Handled = True
End If
End Sub
As you can see we have used the
ControlPaint class to draw the RadioButton / OptionButton.
Download:
DGVCheckBoxAsRadioButton.zip
