c# - Checkbox == true not detected -

i attempting delete row (or rows) listview via checkbox. code have below.. have used same on similar area of site 1 doesn't seem work. check box ticked, delete button pressed , reloads page without deleting.

page load

protected void page_load(object sender, eventargs e) {     dstableadapters.contact_messagestableadapter cmta = new dstableadapters.contact_messagestableadapter();     dstableadapters.messagestableadapter mta = new dstableadapters.messagestableadapter();     dstableadapters.user_messagestableadapter umta = new dstableadapters.user_messagestableadapter();      datatable cmessagetable = cmta.getall();     datatable ownermessagestable = umta.getmessages("owner");     datatable clientmessagestable = umta.getmessages("user");      lvcontact.datasource = cmessagetable;     lvcontact.databind();      lvclientmessages.datasource = clientmessagestable;     lvclientmessages.databind();      lvownermessages.datasource = ownermessagestable;     lvownermessages.databind(); } 

markup:

   <asp:listview id="lvcontact" runat="server" datakeynames="contact_id">       <layouttemplate>         <table id="itemplaceholdercontainer">           <tr>             <th>message id</th>             <th>email address</th>             <th>message</th>             <th>date</th>           </tr>           <tr runat="server" id="itemplaceholder"></tr>         </table>       </layouttemplate>       <itemtemplate>         <tr>           <td>             <asp:checkbox id="chkcontactid" runat="server" autopostback="false" />           </td>           <td>             <asp:label id="lblcontactemail" runat="server" text='<%#eval("email") %>' />           </td>           <td>             <asp:label id="lblcontactmessage" runat="server" text='<%#eval("message") %>' />           </td>           <td>             <asp:label id="lblcontactdate" runat="server" text='<%#eval("date") %>' />           </td>         </tr>       </itemtemplate>     </asp:listview>     <asp:button id="btncontactdelete" runat="server"      text="delete selected messages" onclick="btncontactdelete_click" /> 

code-behind:

protected void btncontactdelete_click(object sender, eventargs e) {     // loop through each row find checked boxes     (int = 0; < lvcontact.items.count; i++)     {         listviewdataitem items = lvcontact.items[i];         int icontactid = convert.toint16(lvcontact.datakeys[items.dataitemindex]["contact_id"]);         checkbox chkbox = (checkbox)items.findcontrol("chkcontactid");         if (chkbox.checked == true)         {             response.write(icontactid);             // if selected deleted             dstableadapters.contact_messagestableadapter cmta = new dstableadapters.contact_messagestableadapter();             cmta.deletemessage(icontactid);         }     }     lvcontact.databind(); } 

do populate listview in page load, might need have

if (!ispostback) {      //fill listview } 

i think when webpage post loosing checked checkboxes.