Dim a As String = BindingSource.Current("Feld")
 
Dim dv As DataView = New DataView(DataSet.Tables("Table"))
dv.Sort = "Spalte_a"
Dim index As Integer = dv.Find(a)
 
If index <> -1 then
  Dim Pos_Copy AS String = dv(Index)("Pos")
 
  dv(Index).BeginEdit()
  dv(Index)("Pos") = dv(Index - 1)("Pos")
  dv(Index).EndEdit()
 
  dv(Index - 1).BeginEdit()
  dv(Index - 1)("Pos") = Pos_Copy
  dv(Index - 1).EndEdit()
End If
 
DataAdapter.Update(DataSet, "Tabelle")
 
BindingSource.Sort = "Pos Asc"