LINQ??? like

DataTable myTable = new DataTable();
        myTable.Columns.Add("test_id", typeof(int));
        myTable.Columns.Add("counts", typeof(int));
        myTable.Columns.Add("c1", typeof(int));
        myTable.Columns.Add("c2", typeof(int));
        myTable.Columns.Add("c3", typeof(int));
        myTable.Columns.Add("c4", typeof(int));
        myTable.Columns.Add("s1", typeof(string));

        myTable.Rows.Add(11, 12, 13, 14, 15, 16, "1x");
        myTable.Rows.Add(21, 22, 23, 24, 25, 26, "2x");
        myTable.Rows.Add(31, 32, 33, 34, 35, 36, "3x");

        DataTable returnTable = new DataTable();
        returnTable.Columns.Add(myTable.Columns[0].ColumnName + myTable.Columns[1].ColumnName + myTable.Columns[2].ColumnName + myTable.Columns[3].ColumnName);

        myTable.AsEnumerable().Select(T => string.Join(",", T[1].ToString() + T[2].ToString() + T[3].ToString() + T[4].ToString())).ToList().ForEach(F => returnTable.Rows.Add(F));

        /*returnTable contains
         * column name = test_idcountsc1c2
         * row1 = 11121314
         * row2 = 21222324
         * row3 = 31323334
         * */