html5 - Input string in correct format. VB.net - New to this so help required -

i having issues page , code behind working on. please see code:

protected sub page_load(sender object, e eventargs) handles me.load          dim dttable datatable = nothing         dim intconnectionid integer = 0          if  page.ispostback              ' user data session             httpcontext.current                  intconnectionid = cint(result.value)             end         end if          ' remove connection         modconnections.delete(intconnectionid)          ' clear desks attahced connection         moddesktext.clearuserdesk(intconnectionid)          using sqlcommand new sqlcommand             sqlcommand                 .commandtext = "usp_connectsdetailedlist"                 .commandtype = commandtype.storedprocedure             end              execute(sqlcommand, dttable)         end using          rep1             .datasource = dttable.defaultview             .databind()         end          if not isnothing(dttable)             dttable.dispose()         end if      end sub  [formatexception: input string not in correct format.]    microsoft.visualbasic.compilerservices.conversions.parsedouble(string value, numberformatinfo numberformat) +213    microsoft.visualbasic.compilerservices.conversions.tointeger(string value) +90  [invalidcastexception: conversion string "" type 'integer' not valid.]    microsoft.visualbasic.compilerservices.conversions.tointeger(string value) +238    frmconnects2.page_load(object sender, eventargs e) in d:\source code\pts\pts online .net - copy\pts online .net\pts online .net stu\frmconnects2.aspx.vb:17    system.web.ui.control.onload(eventargs e) +95    system.web.ui.control.loadrecursive() +59    system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) +678 

on line:

intconnectionid = cint(result.value)  

i getting above error. no matter cannot data convert format need work. understand has nothing right hand side code.

my goal data table, place in text box (<input type="text" id="result" runat="server" />) id="result" , use "id" of record selected in sql remove connection. see table below:

<itemtemplate>                          <tr class="<%# returnvaluesascolor(eval("online"), eval("mobile"), eval("server_proc"))%>">                         <td><%# eval("id").tostring%></td>                         <td><%# eval("user_id").tostring%></td>                         <td><%# eval("user_name").tostring%></td>                         <td><%# eval("workstation_name").tostring%></td>                         <td><%# eval("ip_address").tostring%></td>                         <td><%# eval("connect_date").tostring%></td>                         <td><%# eval("refresh_date").tostring%></td>                         <td><%# eval("app_ver").tostring%></td>                         <td><%# eval("app_date").tostring%></td>                         <td><%# cbool(eval("get_messages_flag")).tostring%></td>                         <td><%# fixnumbers(eval("message_type_flags"))%></td>                         <td><%# eval("online").tostring%></td>                         <td><%# eval("mobile").tostring%></td>                         <td><%# eval("group_name").tostring%></td>                         <td><%# eval("server_proc").tostring%></td>                         <td><input type="submit" class="ui-button ui-widget ui-state-default ui-corner-all" value="delete connection" onclick="cleartext(result); copyid(<%# eval("id").tostring%>);" /></td>                         </tr>                      </itemtemplate> 

js used:

<script>                  function copyid(num) {                     var txt = document.getelementbyid("<%= result.clientid%>").value;                     txt = num;                     document.getelementbyid("<%= result.clientid%>").value = txt;                     }  </script> 

sorry if missed or there lack of info. appreciated.

you haven't shown definition result or result.value educated guess.

try testing null value in database:

if isdbnull(result.value)     intconnectionid = 0  else     intconnectionid = cint(result.value) end if