Create order screen with Checkedboxlist and gridview in C# asp.net

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C#

ASP.NET

i need an order screen in C# asp.net. i googled a loat but can't find any method to do that.
please check that picture
http://i.stack.imgur.com/omni6.png[^]
i want to do like this Checkedboxlist have all items when ever user select an item it should add in gridview.when uncheck it should remove from gridview.

C# Code

protected void Page_Load(object sender, EventArgs e)
        {
            BALL data = new BALL();
            DataSet ds = data.NewOrderLoad();
            GridView1.DataSource = new System.Collections.ArrayList();
            GridView1.DataBind();
            items = new DataTable();
            items = ds.Tables[0];
            if (!IsPostBack)
            {
                
             for (int i = 0; i < items.Rows.Count; i++) //all item names from database
                {
                    ListItem li = new ListItem(items.Rows[i][1].ToString(),
                                           items.Rows[i][0].ToString());
                    CheckBoxList1.Items.Add(li);
                }
            }
        }
protected void CheckBoxList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(string));
            dt.Columns.Add("Name", typeof(string));
            dt.Columns.Add("UnitPrice", typeof(string));
            dt.Columns.Add("Price", typeof(string));
            dt.Columns.Add("Quantity", typeof(string));
            string Id = Selected data;
            string Name = Selected data;
            string UnitPrice = Selected data;
            string Price = Selected data;
            string Quantity =Selected data;
            dt.Rows.Add(Id , Name, UnitPrice, Price, Quantity);
            GridView1.DataSource = dt;
            GridView1.DataBind();

        }

gridview can't maintain view state
help me to make complete order screen start to end.
Please Help me that is my college project.

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" MaintainScrollPositionOnPostback="true" CellPadding="4" ForeColor="#333333" GridLines="None" ShowHeader="True" ShowHeaderWhenEmpty="True" ViewStateMode="Disabled">
                  <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                  <EditRowStyle BackColor="#999999" />
                  <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                  <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                  <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                  <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                  <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                  <SortedAscendingCellStyle BackColor="#E9E7E2" />
                  <SortedAscendingHeaderStyle BackColor="#506C8C" />
                  <SortedDescendingCellStyle BackColor="#FFFDF8" />
                  <SortedDescendingHeaderStyle BackColor="#6F8DAE" />
                   <Columns>
                      <asp:BoundField DataField="Id" HeaderText="Id" ItemStyle-Width="30" HeaderStyle-Width ="30"/>
                      <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="250" HeaderStyle-Width ="250"/>
                      <asp:BoundField DataField="UnitPrice" HeaderText="Unit Price" ItemStyle-Width="75" HeaderStyle-Width ="75" />
                       <asp:BoundField DataField="Price" HeaderText="Price" ItemStyle-Width="75" HeaderStyle-Width ="75" />
                       <asp:BoundField DataField="Quantity" HeaderText="Quantity" ItemStyle-Width="75" HeaderStyle-Width ="75"/>
                 </Columns>
              </asp:GridView>