GridView with checkbox

This article is very simple.Many time developer need to how develop Gridview with checkbox,so we can select single or multiple record to update.
Javascript file

 <script language="javascript" type="text/javascript">  
      function SelectAllCheckboxes(spanChk)  
      {  
           var oItem = spanChk.children;  
           var theBox=(spanChk.type=="checkbox")?spanChk:spanChk.children.item[0];  
           xState=theBox.checked;  
           elm=theBox.form.elements;  
           for(i=0;i if(elm[i].type=="checkbox" && elm[i].id!=theBox.id)  
           {   
                if(elm[i].checked!=xState)  
                elm[i].click();   
           }  
      }  
 </script>  

Html code

 <form id="form1" runat="server">  
      <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="CustomerID" Width="366px" CellPadding="4" ForeColor="#333333" GridLines="None">  
           <Columns>  
                <asp:CommandField ShowSelectButton="True" />  
                <asp:BoundField DataField="CustomerID" HeaderText="CustomerID" InsertVisible="False" ReadOnly="True" SortExpression="PersonID" />  
                <asp:BoundField DataField="Fname" HeaderText="Fname" SortExpression="Fname" />  
                <asp:TemplateField HeaderText="Select">  
                     <ItemTemplate>  
                          <asp:CheckBox ID="chkSelect" runat="server" />  
                     </ItemTemplate>  
                     <HeaderTemplate>  
                          <input id="chkAll" onclick="javascript:SelectAllCheckboxes(this);" runat="server" type="checkbox" />  
                     </HeaderTemplate>  
                </asp:TemplateField>  
           </Columns>   
      </asp:GridView>  
      <br />  
      <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Delete" />   
      <asp:Label ID="lblmsg" runat="server" Text="Label" Visible="false"></asp:Label>  
 </form>  

.cs code

 public partial class GridWithCheck : System.Web.UI.Page  
 {  
   SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["StrConnect"].ToString());  
   protected void Page_Load(object sender, EventArgs e)  
   {  
     if (!IsPostBack)  
     {  
       BindGridView();  
     }  
   }  
   public void BindGridView()  
   {      
     SqlDataAdapter ad = new SqlDataAdapter("select * from tbl_CustomerDetail order by CustomerID", con);  
     DataSet ds = new DataSet();  
     ad.Fill(ds);  
     GridView1.DataSource = ds;  
     GridView1.DataBind();  
   }  
   protected void Button1_Click(object sender, EventArgs e)  
   {   
     foreach (GridViewRow row in GridView1.Rows)  
     {  
       CheckBox cb = ((CheckBox)(row.FindControl("chkSelect")));  
       if (cb != null && cb.Checked)  
       {   
         int custID = Convert.ToInt32(GridView1.DataKeys[row.RowIndex].Value);  
         string sqlstr = "delete from tbl_CustomerDetail where CustomerID='" + custID + "'";  
         SqlCommand mycmd;  
         mycmd = new SqlCommand(sqlstr, con);  
         con.Open();  
         mycmd.ExecuteNonQuery();  
         Page.RegisterStartupScript("pop", "<script>alert('Row deleted')</script>");  
         BindGridView();          
       }  
     }   
   }  
  }  

Thanks & Regards
Santosh