Bind checkboxlist to datatable C#

I have a large table with roughly 70 columns.  I have a checkboxlist listing the column names and when the user checks certain items from that list (limit of 3 for now), it will create a multi line/multi series graph from those selections and use the items selected to create the legend as well.  I can get the graph to create but it is not graphing the columns I select and is just doing the last column in the checkboxlist.  I don't know why it is only doing 1 column and not all the ones selected and I am not sure why the legend creates a series for each item in the checkbox - regardless of what is selected.  

protected void BindChart()
        {
            //Add columns to the DataTable
            string oradb = "Data Source=P3CMS;Persist Security Info=True;User ID=cmsuser;Password=cmssystem";
            OracleConnection cn = new OracleConnection(oradb);
            cn.Open();
            string cmdstr = "";
            string selectedValue = "";

            cmdstr = "SELECT DISTINCT CEM_READING_DATE, BATTERY_NAME, TURN ";

            //Build the IN string by looping through the listbox
            for (int i = 0; i < ListBoxSelection.Items.Count; i++)
            {
                if (ListBoxSelection.Items[i].Selected)
                {
                    selectedValue = selectedValue + ", " + ListBoxSelection.Items[i].Value;
                }
            }

            selectedValue = selectedValue.TrimEnd(',');

            cmdstr = cmdstr + selectedValue + " FROM CEM_READINGS ";

            //Create the WHERE string
            strWhere = "WHERE (CEM_READING_DATE >= TO_DATE('" + tbStartDate.Text + "','MM/DD/YYYY HH:MI:SS AM')) " +
                       "AND (BATTERY_NAME = '" + DropDownList1.SelectedValue + "') " +
                       "AND (TURN = '" + ddlTurn.SelectedValue + "') " +
                       "AND ROWNUM <= 100 " +
                       "ORDER BY CEM_READING_DATE ASC";

            //Add WHERE clause
            cmdstr = cmdstr + strWhere;

            OracleCommand cmd = new OracleCommand(cmdstr, cn);
            OracleDataAdapter adapter = new OracleDataAdapter(cmd);

            DataSet ds = new DataSet();
            adapter.Fill(ds);
            DataTable dt = ds.Tables[0];

            string[] x = new string[dt.Rows.Count];
            int[] y = new int[dt.Rows.Count];
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                x[i] = dt.Rows[i][0].ToString();
                CEMGRAPH.Series[0].XValueType = ChartValueType.DateTime;
			}

            for (int col = 3; col < dt.Columns.Count; col++)
            {
                Series series = new Series();
                string ColName = dt.Columns[col].ColumnName;
                string retVal = string.Empty;
                bool bFound = true;
                
                for (int i = 0; i < CheckBoxList1.Items.Count; i++)
                {
                    if (CheckBoxList1.Items.Count > i)

                        if (CheckBoxList1.Items.Count == i)
                        {
                            selectedValue = selectedValue + ", " + CheckBoxList1.Items[i].ToString();
                        }
                }

                if (bFound)
                {
                    for (int i = 0; i < dt.Rows.Count - 1; i++)
                    {
                        y[i] = Convert.ToInt32(dt.Rows[i][col]);
                    }

                    CEMGRAPH.Series[0].Points.DataBindXY(x, y);
                    CEMGRAPH.Series.Add("Series" + (col).ToString());
                    CEMGRAPH.Series[0].ChartType = System.Web.UI.DataVisualization.Charting.SeriesChartType.Line;

                    CEMGRAPH.Legends["Default"].Enabled = true;
                    CEMGRAPH.Series[0].IsVisibleInLegend = true;
                }
            }
        }