how to access template column in code behind

[ERUM]

i have following code to bind gridview with sql datasource

     <asp:GridView  AllowPaging=True   ID="GridView1" runat="server" 
                                                      DataSourceID=SqlDataSource1  DataKeyNames=userid  
                                                      AutoGenerateColumns="False" BackColor="White" 
                                                      BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" CellPadding="3" 
                                                      Width="449px" style="margin-right: 0px"  PageSize="40">

there is template column in grid

  <asp:TemplateField HeaderText="Approve">
    <ItemTemplate>
         <asp:CheckBox ID="CheckBox1" Enabled=true runat="server" Checked='<%# Bind("Approve") %>' />
        
    </ItemTemplate>
       
</asp:TemplateField>

if it is 0 it checked it(checkbox) otherwise not ,all are enable too
, i want that if it is checked it should become disable ,secondly i write some lines in code behind like row_databound event and put certain break point but it does not stop over that break point

any help