DataGridView Select Column

[LuxCoder]

Hi,

I have added an unbound checkbox column to my DGV. I have two questions on handling it:

1. How to have a checkbox on this Column header, which on checking must check all the rows in the DGV and vice versa?

2. How do i get the Boolean value of the checked rows in DGV on event handling? In other words, how do i know what rows are selected?

Please help.

[jmcilhinney]

I don't know about the first question but for the second you answered it yourself. The Value property of each cell will be True or False, depending on whether the box is checked or not. The Value property of every DataGridViewCell always contains the cell's value.

[LuxCoder]

Anybody any idea on the first part???

[LuxCoder]

I am using the following code to add a select column in my DGV. The header checkbox is enabling me to select/deselect all the displayed rows in DGV but when i try to select an individual row, it doesn't happen.

Dim bForceUnCheck As Boolean = False

Private Sub MDIParentMW_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim checkboxColumn As DataGridViewCheckBoxColumn = New DataGridViewCheckBoxColumn()
        checkboxColumn.Name = "Select"
        checkboxColumn.Width = 25
        checkboxColumn.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter
        'Add it is a First Column
        DataGridView1.Columns.Insert(0, checkboxColumn)
        ' Add Checkbox Column Header
        Dim rect As Rectangle = DataGridView1.GetCellDisplayRectangle(0, -1, True)
        ' set checkbox header to center of header cell. +1 pixel to position correctly.
        rect.X = rect.Location.X + (rect.Width / 1.55)
        Dim checkboxHeader As CheckBox = New CheckBox()
        checkboxHeader.Name = "SELECTALL"
        checkboxHeader.Size = New Size(14, 20)
        checkboxHeader.Location = rect.Location
        AddHandler checkboxHeader.CheckedChanged, AddressOf checkboxHeader_CheckedChanged
        DataGridView1.Controls.Add(checkboxHeader)
End Sub

Private Sub checkboxHeader_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
        If Not bForceUnCheck Then
            DataGridView1.EndEdit()
            'To override the individually selected cells            
            For i As Integer = 0 To DataGridView1.RowCount - 1
                DataGridView1(0, i).Value = CType(DataGridView1.Controls.Find("SELECTALL", True)(0), CheckBox).Checked
            Next
        End If
        bForceUnCheck = False
End Sub

Private Sub DataGridView1_CellContentClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
        If CType(sender, DataGridView).Columns(e.ColumnIndex).Name = "Select" And e.RowIndex >= 0 Then
            Dim dgCB As DataGridViewCheckBoxCell
            dgCB = CType(DataGridView1("Select", e.RowIndex), DataGridViewCheckBoxCell)
            'Uncheck the header checkbox when any of the check box in the row            
            'is deselected            
            If Not CBool(dgCB.EditedFormattedValue) Then
                'Checkbox Unselected                
                If CType(DataGridView1.Controls.Find("SELECTALL", True)(0), CheckBox).Checked Then
                    bForceUnCheck = True
                    CType(DataGridView1.Controls.Find("SELECTALL", True)(0), CheckBox).Checked = False
                End If
            End If
        End If
End Sub

Kindly suggest.