Hi.I would like to help me with my code. I have 2 gridviews. In the first gridview the user can choose with a checkbox every row he wants. These rows are transfered in the second gridview. All these my code does them well.Now, I want to edit the quantity column in second gridview to change the value but i don't know what i must write in edit box. Here is my code:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections;

public partial class ShowLand : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {


        if (!IsPostBack)
        {
            BindPrimaryGrid();
            BindSecondaryGrid();

        }
    }
    private void BindPrimaryGrid()
    {
        string constr = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
        string query = "select * from Land";
        SqlConnection con = new SqlConnection(constr);
        SqlDataAdapter sda = new SqlDataAdapter(query, con);
        DataTable dt = new DataTable();
        sda.Fill(dt);
        gridview2.DataSource = dt;
        gridview2.DataBind();
    }



    private void GetData()
    {
        DataTable dt;
        if (ViewState["SelectedRecords1"] != null)
            dt = (DataTable)ViewState["SelectedRecords1"];
        else
            dt = CreateDataTable();
        CheckBox chkAll = (CheckBox)gridview2.HeaderRow
                            .Cells[0].FindControl("chkAll");
        for (int i = 0; i < gridview2.Rows.Count; i++)
        {
            if (chkAll.Checked)
            {
                dt = AddRow(gridview2.Rows[i], dt);
            }
            else
            {
                CheckBox chk = (CheckBox)gridview2.Rows[i]
                                .Cells[0].FindControl("chk");
                if (chk.Checked)
                {
                    dt = AddRow(gridview2.Rows[i], dt);
                }
                else
                {
                    dt = RemoveRow(gridview2.Rows[i], dt);
                }
            }
        }
        ViewState["SelectedRecords1"] = dt;
    }
    private void SetData()
    {
        CheckBox chkAll = (CheckBox)gridview2.HeaderRow.Cells[0].FindControl("chkAll");
        chkAll.Checked = true;
        if (ViewState["SelectedRecords1"] != null)
        {
            DataTable dt = (DataTable)ViewState["SelectedRecords1"];
            for (int i = 0; i < gridview2.Rows.Count; i++)
            {
                CheckBox chk = (CheckBox)gridview2.Rows[i].Cells[0].FindControl("chk");
                if (chk != null)
                {
                    DataRow[] dr = dt.Select("id = '" + gridview2.Rows[i].Cells[1].Text + "'");
                    chk.Checked = dr.Length > 0;
                    if (!chk.Checked)
                    {
                        chkAll.Checked = false;
                    }
                }
            }
        }
    }
            private DataTable CreateDataTable()
                {
                     DataTable dt = new DataTable();
                     dt.Columns.Add("id");
                     dt.Columns.Add("name");
                     dt.Columns.Add("price");
                     dt.Columns.Add("quantity");
                     dt.Columns.Add("total");
                     dt.AcceptChanges();
                     return dt;
                }
    private DataTable AddRow(GridViewRow gvRow, DataTable dt)
     {
    DataRow[] dr = dt.Select("id = '" + gvRow.Cells[1].Text + "'");
    if (dr.Length <= 0)
    {
        dt.Rows.Add();
        dt.Rows[dt.Rows.Count - 1]["id"] = gvRow.Cells[1].Text;
        dt.Rows[dt.Rows.Count - 1]["name"] = gvRow.Cells[2].Text;
        dt.Rows[dt.Rows.Count - 1]["price"] = gvRow.Cells[3].Text;
        dt.Rows[dt.Rows.Count - 1]["quantity"] = gvRow.Cells[4].Text;
        dt.Rows[dt.Rows.Count - 1]["total"] = gvRow.Cells[5].Text;
        dt.AcceptChanges();
    }
    return dt;
    }

    private DataTable RemoveRow(GridViewRow gvRow, DataTable dt)
    {
    DataRow[] dr = dt.Select("id = '" + gvRow.Cells[1].Text + "'");
    if (dr.Length > 0)
    {
        dt.Rows.Remove(dr[0]);
        dt.AcceptChanges();
    }
    return dt;
    }

    protected void CheckBox_CheckChanged(object sender, EventArgs e)
    {
    GetData();
    SetData();
    BindSecondaryGrid();
    }

    private void BindSecondaryGrid()
    {
    DataTable dt = (DataTable)ViewState["SelectedRecords1"];
    gridview3.DataSource = dt;
    gridview3.DataBind(); 
    }
  }

and the source code is

        <asp:GridView ID="gridview2" runat="server" AutoGenerateColumns="False" 
            DataKeyNames="id" DataSourceID="SqlDataSource5">
          <Columns>
          <asp:TemplateField>
    <HeaderTemplate>
      <asp:CheckBox ID="chkAll" runat="server" onclick = "checkAll(this);"
        AutoPostBack = "true"  OnCheckedChanged = "CheckBox_CheckChanged"/>
    </HeaderTemplate>
    <ItemTemplate>
      <asp:CheckBox ID="chk" runat="server" onclick = "Check_Click(this)"
       AutoPostBack = "true"  OnCheckedChanged = "CheckBox_CheckChanged" />
    </ItemTemplate>
    </asp:TemplateField>
                <asp:BoundField DataField="id" HeaderText="id" InsertVisible="False" 
                    ReadOnly="True" SortExpression="id" />
                <asp:BoundField DataField="name" HeaderText="name" 
                    SortExpression="name" />
                <asp:BoundField DataField="price" HeaderText="price" SortExpression="price" />
              <asp:BoundField DataField="quantity" HeaderText="quantity" 
                  SortExpression="quantity" />
              <asp:BoundField DataField="total" HeaderText="total" SortExpression="total" />
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource5" runat="server" 
            ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
            SelectCommand="SELECT * FROM [Land]"></asp:SqlDataSource>
        <br />
    </div>
    <div>

        <asp:GridView ID="gridview3" runat="server"
        AutoGenerateColumns = "False" DataKeyNames="id" 
        EmptyDataText = "No Records Selected" >
        <Columns>

        <asp:BoundField DataField = "id" HeaderText = "id" />
        <asp:BoundField DataField = "name" HeaderText = "name" ReadOnly="True" />
        <asp:BoundField DataField = "price" HeaderText = "price" 
        DataFormatString="{0:c}" ReadOnly="True" />
        <asp:TemplateField HeaderText="quantity">
        <EditItemTemplate>
            <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("quantity")%>'</asp:TextBox>
        </EditItemTemplate>
        <ItemTemplate>
            <asp:Label ID="Label1" runat="server" Text='<%# Bind("quantity") %>'></asp:Label>
        </ItemTemplate>
       </asp:TemplateField>





   <asp:BoundField DataField = "total" HeaderText = "total" 
        DataFormatString="{0:c}" ReadOnly="True" />
        <asp:CommandField ShowEditButton="True" />

 </Columns>
</asp:GridView>
<asp:Label ID="totalLabel" runat="server"></asp:Label>
<br />

    </div>
   </form>
</body>

</html>