Private Sub GetChildRowsFromDataRelation(table As DataTable)
    Dim rowArray() As DataRow
    Dim relation As DataRelation, row As DataRow
    Dim column As DataColumn, i As Integer     
    For Each relation In  table.ParentRelations
        For Each row In  table.Rows
            rowArray = row.GetParentRows(relation)
            ' Print values of rows.             
            For i = 0 To rowArray.Length - 1                 
                For Each column In  table.Columns
                    Console.WriteLine(rowArray(i)(column))
                Next column
            Next i
        Next row
    Next relation
End Sub

private void GetChildRowsFromDataRelation(DataTable table)
{
    DataRow[] rowArray;
    foreach(DataRelation relation in table.ParentRelations)
    {
        foreach(DataRow row in table.Rows)
        {
            rowArray = row.GetParentRows(relation);
            // Print values of rows.
            for(int i = 0; i < rowArray.Length; i++)
            {
                foreach(DataColumn column in table.Columns)
                {
                    Console.WriteLine(rowArray[i][column]);
                }
            }
        }
    }
}