Visual Basic

Private Sub dgvRows_KeyDown( _
            ByVal sender As Object, _
            ByVal e As System.Windows.Forms.KeyEventArgs) _
            Handles dgvRows.KeyDown
    ' Detect the Enter key
    If e.KeyCode = Keys.Return Then
        ' Determine the currently selected column
        Select Case dgvRows.SelectedCells(0).ColumnIndex
            Case 0
                ' Determine the currently selected row
                Select Case dgvRows.SelectedCells(0).RowIndex
                    Case 0
                        ' Code to manipulate the selected cell at (0,0)
                    Case 1
                        ' Code to manipulate the selected cell at (0,1)
                        '
                        '
                    Case 99
                        ' Etc
                End Select
            Case 1
                '
                '
            Case 99
        End Select
    End If
End Sub

Public Class myDataGridView
    Inherits DataGridView

    Protected Overrides Function ProcessCmdKey( _
              ByRef msg As System.Windows.Forms.Message, _
              ByVal keyData As System.Windows.Forms.Keys) _
              As Boolean

        '** When the Enter key is pressed in the textbox column,
        '** substitute Ctrl^Enter
        If keyData = Keys.Enter Then
            SendKeys.SendWait("^{ENTER}")
            Return True
        Else
            Return MyBase.ProcessDialogKey(keyData)
        End If

    End Function

End Class

Public Class Form1

    Dim dgv As New myDataGridView

    Private Sub Form1_Load(ByVal sender As System.Object, _
                           ByVal e As System.EventArgs) _
                           Handles MyBase.Load

        '** Add the datagridview to the form
        Controls.Add(dgv)
        dgv.Left = 10
        dgv.Top = 10

        '** Add a textbox column
        Dim dgvCol As New DataGridViewTextBoxColumn
        With dgvCol
            .HeaderText = "Text Column"
            .Name = "chdrTextCol"
            .Width = 130
        End With
        dgv.Columns.Add(dgvCol)
        dgvCol = Nothing

        '** Add a row
        dgv.Rows.Add()

    End Sub

End Class