''' <summary>Berechnung von Rängen in Spalten</summary>
    ''' <param name="dt">Tabelle mit Rohwerten</param>
    ''' <param name="spalten">Array: Spaltenbezeichner für Rangberechnung</param>
    ''' <param name="dt_out">Rückgabe: Tabelle mit Rangwerten</param>
    Public Sub vRank3(ByVal dt As DataTable, ByVal spalten() As String, _
                      ByVal dt_out As DataTable)
 
        If dt_out Is Nothing Then dt_out = New DataTable
        If dt_out.Rows.Count > 0 Then dt_out.Rows.Clear()
        If dt_out.Columns.Count > 0 Then dt_out.Columns.Clear()
 
        For i As Integer = 0 To spalten.Length - 1
            dt_out.Columns.Add(spalten(i), GetType(Integer))
        Next i
 
        Dim val As Decimal, rnk As Integer
        For row As Integer = 0 To dt.Rows.Count - 1
            For c1 As Integer = 0 To spalten.Length - 1
                val = dt.Rows(row)(spalten(c1))
                rnk = 1
                For c2 As Integer = 0 To spalten.Length - 1
                    If val > dt.Rows(row)(spalten(c2)) Then rnk += 1
                Next c2
                If c1 = 0 Then
                    Dim r As DataRow = dt_out.NewRow
                    dt_out.Rows.Add(r)
                End If
                dt_out(row)(spalten(c1)) = rnk
            Next c1
        Next row
    End Sub