Get gridview row values when checkbox checked

I have a gridview with checkboxes to select the row. On checking the checkbox I need to get the row values into a string/session. Below is the code

       <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowCancelingEdit="GridView1_RowCancelingEdit"    
            OnRowEditing="GridView1_RowEditing"  OnRowUpdating="GridView1_RowUpdating"  OnRowDeleting="GridView1_OnRowDeleting"  OnPageIndexChanging="GridView1_PageIndexChanging" OnSelectedIndexChanged="GridView1_SelectedIndexChanged"  Width ="1000px" class="grid" AllowPaging="True" PagerSettings-FirstPageText="First" PagerSettings-LastPageText="Last" PageButtonCount="2" PagerSettings-Mode="NumericFirstLast" PageSize="5">


                <PagerSettings Mode="NumericFirstLast" PageButtonCount="2"  FirstPageText="First" LastPageText="Last"/> 


       <Columns>   

           <asp:TemplateField HeaderText="Id">   
                <ItemTemplate>   
                   <asp:CheckBox ID="CheckBox3" runat="server" />
                </ItemTemplate>   
            </asp:TemplateField>   
            <asp:TemplateField HeaderText="Connection">   
                <ItemTemplate>   
                    <asp:Label ID="lbl_conn" runat="server" Text='<%#Eval("Connection") %>'></asp:Label>   
                </ItemTemplate>   
            </asp:TemplateField>   

                            <asp:TemplateField HeaderText="UserID">   
                <ItemTemplate>   
                    <asp:Label ID="lbl_Usrid" runat="server" Text='<%#Eval("UserID") %>'></asp:Label>   
                </ItemTemplate>   
                <EditItemTemplate>   
                    <asp:TextBox ID="txt_Usrid" runat="server" Text='<%#Eval("UserID") %>'></asp:TextBox>   
                </EditItemTemplate>   
            </asp:TemplateField> 
            <asp:TemplateField HeaderText="Password">   
                <ItemTemplate>   
                    <asp:Label ID="lbl_pwd" runat="server" Text='<%#Eval("Password") %>'></asp:Label>   
                </ItemTemplate>   
                <EditItemTemplate>   
                    <asp:TextBox ID="txt_pwd" runat="server" Text='<%#Eval("Password") %>'></asp:TextBox>   
                </EditItemTemplate>   
            </asp:TemplateField> 
            <asp:TemplateField HeaderText="Connection Name">   
                <ItemTemplate>   
                    <asp:Label ID="lbl_conName" runat="server" Text='<%#Eval("Connection_Name") %>'></asp:Label>   
                </ItemTemplate>   
                <EditItemTemplate>   
                    <asp:TextBox ID="txt_conName" runat="server" Text='<%#Eval("Connection_Name") %>'></asp:TextBox>   
                </EditItemTemplate>   
            </asp:TemplateField>   


               <asp:TemplateField HeaderText="Edit">   
                <ItemTemplate>   
                    <asp:Button ID="btn_Edit" runat="server"  Text=" Edit" class=" btnEdit"  CommandName="Edit" />   
                </ItemTemplate>   
                <EditItemTemplate>   
                    <asp:Button ID="btn_Update" runat="server" class=" btnEdit" Text="Update" CommandName="Update"/>   
                    <asp:Button ID="btn_Cancel" runat="server" class=" btnEdit" Text="Cancel" CommandName="Cancel"/>   
                </EditItemTemplate>   
            </asp:TemplateField>  
           <asp:TemplateField HeaderText="Delete">   
                <ItemTemplate>   
                    <asp:Button ID="btn_Delete" runat="server" class=" btnDelete" Text="Delete" CommandName="Delete" OnClientClick="return confirm('Are you sure you want to delete this event?')" />   
                </ItemTemplate>   

            </asp:TemplateField> 
        </Columns>   



    </asp:GridView>   

There is a button below the grid. on click of the button I need to get the values.

  protected void LinkButton1_Click(object sender, EventArgs e)
    {



        foreach (GridViewRow item in GdvTestData.Rows)
        {


            CheckBox chk = (item.FindControl("CheckBox3") as CheckBox);
            if (chk.Checked)
            {

             string conn = item.Cells[1].Text;


            }
        }

}

But am getting null value for string conn = item.Cells[1].Text; where am I going wrong