'Deklarationen
Dim dt As New DataTable
Dim bs As New BindingSource
 
Dim tbx As New TextBox With {.Parent = Me}
 
'Spalten und Daten
dt.Columns.Add("ID", GetType(Integer))
dt.Columns.Add("E.ID", GetType(String)) 'kritische Spalte
dt.Columns.Add("E_ID", GetType(String), "E.ID") 'Expression-Column
 
dt.Rows.Add(1, "10")
dt.Rows.Add(2, "20")
 
'Datenbindung
bs.DataSource = dt
tbx.DataBindings.Add(New Binding("Text", bs, "E_ID"))
 
 
'Vom Benutzer geänderte Spalten-Werte müssen explizit eingetragen werden
Private Sub tbx_KeyDown(sender As Object, _
    e As System.Windows.Forms.KeyEventArgs) Handles tbx.KeyDown
 
    If e.KeyCode = Keys.Return Then
       Dim r As DataRowView = DirectCast(bs(bs.Position), DataRowView)
       r.Item("E.ID") = tbx.Text
       bs.EndEdit()
    End If
End Sub