A bound DataGridView ComboBox Column doesn’t allow user input. You might come across a situation where you need to make it easier for the user to select an item from the ComboBox and at the same time allow them to just enter free text.
The trick is to make the ComboBox column without a DataSource and then you load the items by code. Also you have to handle a couple of stuff such as the EditingControlShowing event to convert the ComboBox style to be DropDown instead of DropDownList, and some other handling to commit the ComboBox change.
I will leave you with the code:
Private Sub MyForm_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load 'Get ComboBox items Me.ComboBoxTableAdapter.Fill(Me.MyDataSet.ComboBoxTable) 'Fill the ComboBox Dim row As DataRow For Each row In Me.MyDataSet.ComboBoxTable 'Generic list used as a trick to have the ComboBox Items added with Value MyComboBox.Items.Add(New GenericListItem(Of String)(row.Item("ColName"), row.Item("ColValue"))) Next Me.GridTableAdapter.Fill(Me.MyDataSet.GridTable) 'Adding Grid handler to detect change in run time AddHandler MyDataGridView.CurrentCellDirtyStateChanged, AddressOf MyDataGridView_CurrentCellDirtyStateChanged End Sub 'Change ComboBox style to DropDown Private MyDataGridView_EditingControlShowing(ByVal sender As Object, ByVal e As MyDataGridViewEditingControlShowingEventArgs) Handles MyDataGridView.EditingControlShowing If TypeOf e.Control Is ComboBox Then Dim cb As ComboBox = TryCast(e.Control, ComboBox) cb.DropDownStyle = ComboBoxStyle.DropDown End If 'When an item is selected from the ComboBox update the cell value If MyDataGridView.Columns(MyDataGridView.CurrentCell.ColumnIndex).Name = "MyComboBox" Then Dim selectedComboBox As ComboBox = DirectCast(e.Control, ComboBox) RemoveHandler selectedComboBox.SelectionChangeCommitted, AddressOf selectedComboBox_SelectionChangeCommitted AddHandler selectedComboBox.SelectionChangeCommitted, AddressOf selectedComboBox_SelectionChangeCommitted End If End Sub Private Sub selectedComboBox_SelectionChangeCommitted(ByVal sender As Object, ByVal e As EventArgs) Try Dim selectedCombobox As ComboBox = DirectCast(sender, ComboBox) If selectedCombobox.SelectedItem IsNot Nothing Then 'Use the List we created earlier so we could retrieve the Value instead of the diplayed text Dim oItem As GenericListItem(Of String) = CType(selectedCombobox.SelectedItem, GenericListItem(Of String)) Me.MyDataGridView.Item("ColumnName", MyDataGridView.CurrentCell.RowIndex).Value = oItem.Value() End If Catch ex As Exception MessageBox.Show(ex.Message) End Try End Sub Private Sub MyDataGridView_CurrentCellDirtyStateChanged(ByVal sender As Object, ByVal e As EventArgs) Handles MyDataGridView.CurrentCellDirtyStateChanged 'Commit the change which was in run time so the Value changed event happens and then allow one check box If MyDataGridView.IsCurrentCellDirty Then MyDataGridView.CommitEdit(MyDataGridViewDataErrorContexts.Commit) End If End Sub Private Sub MyDataGridView_CellValidating(sender As Object, e As System.Windows.Forms.MyDataGridViewCellValidatingEventArgs) Handles MyDataGridView.CellValidating 'Allow user to enter new values for all MyDataGridViewComboBox controls in the MyDataGridView If (TypeOf CType(sender, MyDataGridView).EditingControl Is MyDataGridViewComboBoxEditingControl) Then Dim cmb As MyDataGridViewComboBoxEditingControl = CType(CType(sender, MyDataGridView).EditingControl, MyDataGridViewComboBoxEditingControl) If Not cmb Is Nothing Then Dim grid As MyDataGridView = cmb.EditingControlMyDataGridView Dim value As Object = cmb.Text '// Add value to list if not there If cmb.Items.IndexOf(value) = -1 Then '// Must add to both the current combobox as well as the template, to avoid duplicate entries... cmb.Items.Add(value) Dim cmbCol As MyDataGridViewComboBoxColumn = CType(grid.Columns(grid.CurrentCell.ColumnIndex), MyDataGridViewComboBoxColumn) If Not cmbCol Is Nothing Then cmbCol.Items.Add(value) End If End If grid.CurrentCell.Value = value End If End If ''Following Works for a specific combobox /////////// 'If e.ColumnIndex = MyMyDataGridView.Columns("MyDataGridViewComboBoxColSize").Index Then 'CType(sender, MyDataGridView).CurrentCell.ColumnIndex ' 'Dim cmb As ComboBox = CType(e.Control, ComboBox) ' Dim cmb As MyDataGridViewComboBoxEditingControl = CType(CType(sender, MyDataGridView).EditingControl, MyDataGridViewComboBoxEditingControl) ' If Not cmb Is Nothing Then ' Dim grid As MyDataGridView = cmb.EditingControlMyDataGridView ' Dim value As Object = cmb.Text ' '// Add value to list if not there ' If cmb.Items.IndexOf(value) = -1 Then ' '// Must add to both the current combobox as well as the template, to avoid duplicate entries... ' cmb.Items.Add(value) ' Dim cmbCol As MyDataGridViewComboBoxColumn = CType(grid.Columns(grid.CurrentCell.ColumnIndex), MyDataGridViewComboBoxColumn) ' If Not cmbCol Is Nothing Then ' cmbCol.Items.Add(value) ' End If ' grid.CurrentCell.Value = value ' End If ' End If 'End If End Sub Public Class GenericListItem(Of T) Private mText As String Private mValue As T Public Sub New(ByVal pText As String, ByVal pValue As T) mText = pText mValue = pValue End Sub Public ReadOnly Property Text() As String Get Return mText End Get End Property Public ReadOnly Property Value() As T Get Return mValue End Get End Property Public Overrides Function ToString() As String Return mText End Function End Class
I hope this helps, and if you have any question let me know.
Happy coding 🙂