ASP.NET

<Columns>
        <asp:BoundField DataField = "Name1" HeaderText = "NAME" />
        <asp:BoundField DataField ="Name2" HeaderText = "NAME2"/>
        <asp:BoundField DataField = "Name3" HeaderText = "NAME3"/>
        <asp:TemplateField>
           <ItemTemplate>
              <asp:CheckBox id ="chkAgency" runat="server"  Enabled />
           </ItemTemplate>
        </asp:TemplateField>
 </Columns>

    <asp:GridView ID="GridView1" AutoGenerateColumns="False" runat="server" 
        DataSourceID="SqlDataSource1">
        <Columns>
            <asp:TemplateField>
            <ItemTemplate>
            <asp:CheckBox ID="chkAgency" runat="server" />
            </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <ItemTemplate>                     
            
            <asp:Label ID="lblid" runat="server" Text='<%# Eval("ID")%>'></asp:Label>
            </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField = "ID" HeaderText = "ID" InsertVisible="False" 
                ReadOnly="True" SortExpression="ID" />
            <asp:BoundField DataField ="Descr" HeaderText = "Descr" SortExpression="Descr"/>
            <asp:BoundField DataField = "LongName" HeaderText = "LongName" 
                SortExpression="LongName"/>
            <asp:BoundField DataField="Capacity" HeaderText="Capacity" 
                SortExpression="Capacity" />
            <asp:BoundField DataField="Note" HeaderText="Note" SortExpression="Note" />
     </Columns>
    </asp:GridView>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:TTBLv3MasterConnectionString %>" 
        SelectCommand="select * from dbo.TBL_VENUE"></asp:SqlDataSource>
<asp:Button ID="btntest" Text="Test" runat="server" onclick="btntest_Click" /> 

protected void btntest_Click(object sender, EventArgs e)
   {
       foreach (GridViewRow row in GridView1.Rows)
       {

           CheckBox chk = (CheckBox)row.FindControl("chkAgency");


           Label lblid = (Label)row.FindControl("lblid");

           List<string> lstList = new List<string>();

           if (chk != null && chk.Checked)
           {
               //Response.Cookies["thistestcookie"].Value = row.Cells[0].Text.ToString();
               lstList.Add(lblid.Text);
           }
       }
   }

HttpContext.Current.Session["MySession"].ToString();

if(Session["Usernane"] == null)
{
response.redirect("Login.aspx",false);
}