ขอความกรุณาด้วยครับ เรื่องการเปรียบเทียบข้อมูลระหว่าง Datatable

  DataTable data2 = new DataTable();
            data2.Columns.Add(new DataColumn("num",typeof(string)));
            data2.Columns.Add(new DataColumn("name", typeof(string)));
            data2.Columns.Add(new DataColumn("sum", typeof(int)));

            dt.Merge(dtfcd);
            dt.AcceptChanges();

            DataView view = new DataView();
            view = dt.DefaultView;
            view.Sort = view.Table.Columns[0].ColumnName;
            dt = view.ToTable();

            int data = 0;
            int count = 0;
            int previous = 1;
            string name = "";
            string sum = "";

            foreach (DataRow dr in dt.Rows)
            {
                data = int.Parse(dr[0].ToString());
                name = dr[1].ToString();
                if(previous == null)
                {
                    count = 1;
                }
                else if (previous != data)
                {
                    DataRow drnew = data2.NewRow();
                    drnew["num"] = previous.ToString();
                    drnew["name"] = name;
                    drnew["sum"] = count;
                    data2.Rows.Add(drnew);

                    count = 1;
                }
                else if (previous == data)
                {
                    count++;
                }
                previous = data;


            }
            dataGridView1.DataSource = data2;
            

            int i = 0;
            int datafcd = int.Parse(dtfcd.Rows[i][2].ToString());
            string branchca = "";
            string branchcaprevious = "";
            int printca = 0;
            int countfcd = 0;
            int datapreviousfcd = 0;
            int datapreviousfcd2 = 0;



            foreach (DataRow dr2 in data2.Rows)
            {
                datapreviousfcd = int.Parse(dr2[0].ToString());
                datapreviousfcd2 = int.Parse(dr2[0].ToString());
                branchca = dr2[1].ToString();
                printca = int.Parse(dr2[2].ToString());
                if (datapreviousfcd == null)
                {
                    countfcd = 0;
                }
                else if (datapreviousfcd != datafcd)
                {
                    DataRow dr3 = data3.NewRow();
                    dr3["Branch_ID"] = datapreviousfcd.ToString("0##");
                    dr3["Branch_Name"] = branchcaprevious;
                    dr3["Print"] = printca;
                    double sumoutsource = printca * 0.85;
                    string outsource = sumoutsource.ToString("#,##0.00");
                    dr3["Outsource"] = outsource;
                    double sumposttage = printca * 11;
                    string posttage = sumposttage.ToString("#,##0.00");
                    dr3["Posttage"] = posttage;
                    dr3["PrintFCD"] = countfcd;





                    data3.Rows.Add(dr3);
                    countfcd = 1;
                }
                else if (datapreviousfcd == datafcd)
                {
                    countfcd++;
                }
                i++;
                datapreviousfcd = datapreviousfcd2;
                branchcaprevious = branchca;

            }

            dataGridView1.DataSource = data3;

            DataTable data2 = new DataTable();
            data2.Columns.Add(new DataColumn("num",typeof(string)));
            data2.Columns.Add(new DataColumn("name", typeof(string)));
            data2.Columns.Add(new DataColumn("sum", typeof(int)));
            int i = 0;
            int count = 0;
            int table1 = 1;
            int table2 = 0;
            int current = 0;
            foreach (DataRow dr in dt.Rows )
            {
                current = int.Parse(dr[0].ToString());
                table2 = int.Parse(dtfcd.Rows[i][0].ToString());
                if (table1 == null)
                {
                    count = 1;
                }
                else if (table1 != table2)
                {
                    DataRow drnew = data2.NewRow();
                    drnew["num"] = table1;
                    drnew["sum"] = count;
                    data2.Rows.Add(drnew);

                    count = 0;
                    i++;
                }
                else if (table1 == table2)
                {
                    count++;
                    i++;
                }
                table1 = current;
                i = 0;
            }
            dataGridView1.DataSource = data2;