VB 2005 DataGridView : How Do I Work With The DGV Combobox Column?

Q: How do I add a ComboboxColumn at design time?

A: After you have added the dataGridView to your form, it should give you a little screen where you can select Add Columns,

and specify the name, and Type. You could also at any time, just right click the Datagridview, select Add Columns, and

select all the necessary options there.

Q: How do I add a Combobox column at run time?

A: All you need to do is to declare a DataGridViewComboBoxColumn object, set the desited properties, and add it to the

DataGridView's Columns collection. Here is a small example :

Code:

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    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim NewColumn As New DataGridViewComboBoxColumn() 'Declare new DGV CC

        With NewColumn 'Set Properties
            .DataPropertyName = "NewColumn" 'Name
            .HeaderText = "New Column" 'Heading
            .DropDownWidth = 160 'Width Of DropDown Box
            .Width = 90 'Display Width
            .MaxDropDownItems = 5 'How Many Items To Drop Down At A Time
            .FlatStyle = FlatStyle.Flat 'Appearance
            .Items.Add("1") 'Add Some Text Items
            .Items.Add("2")
            .Items.Add("3")
            .Items.Add("4")
            .Items.Add("5")
            .Items.Add("6")
            .Items.Add("7")
            .Items.Add("8")
            .Items.Add("9")
            .Items.Add("10")
        End With
        DataGridView1.Columns.Add(NewColumn) 'Add The Column

    End Sub

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Once you have added this code, you can run your project and will notice that the new column has been added at the back of the

datagridview. You can select any of the items we've added from the list.

Q: How can I allow the user to type text into the newly created Comboboxcolumn, and persist it?

A: All You need is the DataGridView's EditingControlShowing event ( To allow for data entry ), and the DataGridView's

CellValidating event, to ensure persistance of the typed value. Add the following code :

Code:

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    Private Sub DataGridView1_CellValidating(ByVal sender As Object, ByVal e As

System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles DataGridView1.CellValidating
            'Create a New ComboBoxColumn Object, And Cast The dataGridView's Column To That
            Dim comboBoxColumn As DataGridViewComboBoxColumn = CType(DataGridView1.Columns(5), DataGridViewComboBoxColumn)
            'If In ComboBoxColumn
            If (e.ColumnIndex = comboBoxColumn.DisplayIndex) Then
                If (Not comboBoxColumn.Items.Contains(e.FormattedValue)) Then
                    'Add The Text Entered By The User
                    comboBoxColumn.Items.Add(e.FormattedValue)
                    'Make Sure Value Stays Displayed ( May HAve To Enter Value Twice )
                    DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value =

comboBoxColumn.Items(comboBoxColumn.Items.Count - 1)
                End If
            End If
    End Sub

    Private Sub DataGridView1_EditingControlShowing(ByVal sender As Object, ByVal e As

System.Windows.Forms.DataGridViewEditingControlShowingEventArgs) Handles DataGridView1.EditingControlShowing
        'If In ComboBox Column
        If (DataGridView1.CurrentCellAddress.X = DataGridView1.Columns(5).DisplayIndex) Then
            'Cast To Normal ComboBox
            Dim cb As ComboBox = CType(e.Control, ComboBox)
            If (cb IsNot Nothing) Then
                'Change Style To DropDown, To Allow For Data Entry
                cb.DropDownStyle = ComboBoxStyle.DropDown
            End If

        End If
    End Sub

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I am attaching a working sample with this post.

Q: Where can I find a more detailed discussion about this topic?

A:
DataGridViewComboBox problem!

DataGirdViewComboBox saving problem

Editing Text in a DataGridViewComboBoxColumn