Delete the selected record instance in the gridview with checkbox in ASP. net2.0!

1   < ASP: gridview ID = "Gridview1" Runat = "Server" Autogeneratecolumns = "False" Pagesize = "5"  
2 Width = "Pixel PX" Allowpaging = "True" Allowsorting = "True"
3 Datakeynames = "Db1_1, db1_2" Onrowdeleting = "Gridview1_rowdeleting" Onpageindexchanging = "Gridview1_pageindexchanging" Onrowdatabound = "Gridview1_rowdatabound" Onsorting = "Gridviewappssorting" Height = "279px"   >
4 < Columns >
5 < ASP: templatefield Headertext = "No"   >
6 < Itemtemplate >
7 <% # This. gridview1.pageindex * This. gridview1.pagesize + This. gridview1.rows. Count +   1 %>
8 </ Itemtemplate >
9 </ ASP: templatefield >
10 < ASP: templatefield Headertext = "Select"   >
11 < Itemtemplate >
12 < ASP: checkbox ID = "Chkselect" Runat = "Server"   > </ ASP: checkbox >
13 </ Itemtemplate >
14 </ ASP: templatefield >
15 < ASP: templatefield Headertext = "Operation" Showheader = "False" >
16 < Itemtemplate >
17 < ASP: linkbutton ID = "Lbtndelete" Runat = "Server" Causesvalidation = "False" Commandname = "Delete"
18 Text = "Delete" Onclientclick = "Return confirm ('Are you sure you want to delete it? ');" > </ ASP: linkbutton >
19 </ Itemtemplate >
20 </ ASP: templatefield >
21 </ Columns >
22 < Alternatingrowstyle Backcolor = "Aquamarine"   />
23 </ ASP: gridview > 1   < ASP: checkbox ID = "Chkselectall" Runat = "Server" Text = "Select all" Oncheckedchanged = "Chkselectall_checkedchanged" Autopostback = "True"   > </ ASP: checkbox >
2 < ASP: button ID = "Btndelete" Runat = "Server" Text = "Delete" Onclick = "Btndelete_click" /> 1 Protected   Void Btndelete_click ( Object Sender, eventargs E)
2 {
3 String Strdelete =   "" ;
4 For ( Int I =   0 ; I <   This . Gridview1.rows. Count; I ++ )
5 {
6 String Label;
7 Bool Ischecked = (Checkbox) gridview1.rows [I]. findcontrol ( " Chkselect " ). Checked;
8 Label = (Label) gridview1.rows [I]. findcontrol ( " Labxh " ). Text;
9 If (Ischecked)
10 {
11 Strdelete =   " Db1_1 "   +   " = "   + Label;
12 }
13 }
14 Conn. runsql ( " Delete from db1 where "   + Strdelete
15 This . Chkselectall. Checked =   False ;
16 Gridviewbind ();
17 }
18  
19 Protected   Void Chkselectall_checkedchanged ( Object Sender, eventargs E)
20 {
21 // Retrieve the checkbox attribute by traversing the gridview row
22 For ( Int I =   0 ; I <   This . Gridview1.rows. Count; I ++ )
23 {
24 (Checkbox) gridview1.rows [I]. findcontrol ( " Chkselect " ). Checked =   This . Chkselectall. checked;
25 }
26 }