Dim dt As New DataTable()
 
        '// Füllen	
 
 
        dt.Columns.Add("art")
        dt.Columns.Add("Vorname")
        dt.Columns.Add("Nachname")
 
        Dim dr As DataRow
        dr = dt.NewRow
        dr("art") = "test"
        dr("Vorname") = "aaa"
        dr("Nachname") = "bbb"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("art") = "test2"
        dr("Vorname") = "ccc"
        dr("Nachname") = "ddd"
        dt.Rows.Add(dr)
 
        dr = dt.NewRow
        dr("art") = "test"
        dr("Vorname") = "aaa"
        dr("Nachname") = "bbb"
        dt.Rows.Add(dr)
        ' usw... 
 
        Dim dtTmp As New DataTable()
        Dim Id As String ' = -1
        dtTmp = dt.Clone
        Dim r As DataRow
        For Each r In dt.Rows
            If art = "" OrElse Not art = Integer.Parse(r("Id")) Then
                dtTmp.ImportRow(r)
                Id = Integer.Parse(r("Id").ToString)
            End If
        Next
 
        dt = dtTmp