how to add checkbox to datagrid

Question

Hi
    iam a fresher can any one helpme out how to add checkbox to a datagrid. using c#

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="ShiftUpdate.aspx.cs" Inherits="Manual_Sanctions_ShiftUpdate" Title="Untitled Page" %>
<%@ Register Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"  Namespace="System.Web.UI" TagPrefix="asp" %>
<%@ Register src="~/UserControl/Calender.ascx" tagname="Calender" tagprefix="uc1" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<%@ Register src="~/UserControl/TimeFormate.ascx" tagname="TimeFormate" tagprefix="uc3" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<table id="Table33"  runat="server" class="TableList"  width="100%">
<tr>
<td>
<table id="Table5"  runat="server" class="TableList"  width="100%">
<tr>
     <td style="width: 284px">Shift Updation</td>
</tr>
</table>
<table id="Table1"  runat="server" class="TableList"  width="100%">
<tr>
     <td style="width: 284px">Date Range</td>
</tr>
<tr>
  <td style="width: 284px">From Date<uc1:Calender ID="Calender1" runat="server" /></td>
  <td>To Date<uc1:Calender ID="Calender2" runat="server" /></td>
</tr>
<tr>
    <td style="width: 284px">Selection Mode</td>
</tr>
<tr>
     <td style="width: 284px"><asp:RadioButtonList ID="RadioButtonList1" runat="Server" Height="74px">
             <asp:ListItem Text="Departmentwise" Value="Departmentwise"></asp:ListItem>
             <asp:ListItem Text="Categorywise" Value="Categorywise"></asp:ListItem>
             <asp:ListItem Text="Gradewise" Value="Gradewise"></asp:ListItem>
          </asp:RadioButtonList>
      </td>
</tr>
</table>
<table id="Table2"  runat="server" class="TableList" cellpadding="1" cellspacing="1"  width="100%" >
<tr>
<td style="width: 189px">Applicable</td>
<td style="width: 197px">Applicable Employees</td>
</tr>
</table>
<table id="Table25"  runat="server" class="TableList" cellpadding="1" cellspacing="1" >
 <tr>
 <td style="width: 224px; height: 121px;"><asp:GridView ID="dgApplicable"
 runat="server" AutoGenerateColumns="False" Width="136%"
 AllowSorting="True" AllowPaging="True" PageSize="20" onrowediting="dgApplicable_RowEditing"
 onpageindexchanging="dgApplicable_PageIndexChanging" Height="127px"
         style="margin-right: 75px"
         onselectedindexchanged="dgApplicable_SelectedIndexChanged" >
 <Columns>
 <asp:BoundField DataField="Code" HeaderText="Code" SortExpression="Code ASC"></asp:BoundField>
 <asp:BoundField DataField="Category" HeaderText="Category"></asp:BoundField>
 </Columns>
 </asp:GridView>                 
 </td>
<td style="height: 135px; width: 42px;"><asp:Button id="Button1" Text="-&gt;" runat="server" style="width: 51px" Font-Bold="True" ForeColor="Black" Width="87px" Height="26px"/></td>
  <td>
  <asp:GridView ID="dgAppEmployees" runat="server" AutoGenerateColumns="False" Width="31%"
      AllowSorting="True" AllowPaging="True" PageSize="20" onrowediting="dgAppEmployees_RowEditing"
      onpageindexchanging="dgAppEmployees_PageIndexChanging" Height="51px" >
      <Columns>
       <asp:BoundField DataField="EmpCode" HeaderText="EmpCode" SortExpression="Code ASC"></asp:BoundField>
       <asp:BoundField DataField="Name" HeaderText="Name"></asp:BoundField>
       </Columns>
       </asp:GridView> 
 </td>
 </tr>            
  <tr>
 <td colspan="1" valign="top" style="width: 224px">
 <asp:CheckBox ID="CheckBox1" runat="server" Text="Select" CssClass="tableList" Height="25px" Width="126px"></asp:CheckBox>
 </td>
 <td></td>
 <td><asp:CheckBox ID="CheckBox2" runat="server" Text="Select" CssClass="tableList" Height="25px" Width="126px"></asp:CheckBox></td>
 </tr>
</table>
</td>
<td>
<table>
<tr>
    <td style="width: 189px">Change Type</td>
    </tr>
    <tr>
   <td><asp:RadioButton ID="radFix" runat="server" Text="Fix Shift" />
    <asp:RadioButton ID="radRotation" runat="server" Text="Rotation" />
    <asp:RadioButton ID="radweekoff" runat="server" Text="Weekoff" />
    <tr>
          <td>
              &nbsp;        
          </td>
    </tr>
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" Width="176px"
      AllowSorting="True" AllowPaging="True" PageSize="20"  Height="51px" >
      <Columns>
       <asp:BoundField DataField="Code" HeaderText="Code" SortExpression="Code ASC"></asp:BoundField>
       <asp:BoundField DataField="InTime" HeaderText="InTime"></asp:BoundField>
       <asp:BoundField DataField="OutTime" HeaderText="OutTime"></asp:BoundField>
       <asp:BoundField DataField="LocationCode" HeaderText="LocationCode"></asp:BoundField>
       <asp:BoundField DataField="            " HeaderText="             "></asp:BoundField>
       </Columns>
       </asp:GridView>                 
 </td>     
  </tr>
 
  <tr>
     <td colspan="1" style="width: 284px"><asp:Button id="Button2" Text="UPDATE" runat="server" />
     <asp:Button id="Button3" Text="EXIT" runat="server" /></td>
 </tr>
</table>

</td>
</tr>
</table>
<table id="Table13"  runat="server" class="TableList" cellpadding="1" cellspacing="1" >
 
</table>


</asp:Content>