Compare Rows of Two DataTables and copy matching rows in Third DataTable using C#

        DataTable dt1 = new DataTable();
        dt1.Columns.AddRange(new DataColumn[1] { new DataColumn("UserId") });
        dt1.Rows.Add("4");
        dt1.Rows.Add("5");
        dt1.Rows.Add("6");
        dt1.Rows.Add("7");
        dt1.Rows.Add("8");
        dt1.Rows.Add("11");
        dt1.Rows.Add("13");

        DataTable dt2 = new DataTable();
        dt2.Columns.AddRange(new DataColumn[2] { new DataColumn("UserId"), new DataColumn("Message") });

        dt2.Rows.Add("4", "abc");
        dt2.Rows.Add("5", "sdf");
        dt2.Rows.Add("6", "rty");
        dt2.Rows.Add("13", "poik");
        dt2.Rows.Add("15", "fgh");
        dt2.Rows.Add("17", "rfjfjf");

        DataTable dt3 = dt2.Clone();
        foreach (DataRow row1 in dt1.Rows)
        {
            foreach (DataRow row2 in dt2.Rows)
            {
                if (row1["UserId"].ToString() == row2["UserId"].ToString())
                {
                    dt3.ImportRow(row2);
                }
            }
        }