javascript - KnockoutJS Select item from foreach -

i have foreach binding

<table id="table_operationsgroup">     <tbody data-bind="foreach: groupoperationsgroup">         <!-- ko if: $index() < $root.groupoperationsgroup().length - 1 -->         <tr>             <td>                 <select data-bind="changegroup: groupoperations,options: operators, optionstext: 'name', value: groupoperations" style="width: 105px;margin-top:5px !important;margin-bottom:5px !important;margin-left:0px !important;"></select>             </td>         </tr>         <!-- /ko -->     </tbody> </table> 

js

ko.bindinghandlers.changegroup = {     update: function (element, valueaccessor, allbindingsaccessor, viewmodel, bindingcontext) {         //some code work select     } };   var groupoperationstemplate = function () {     var self = this;     self.groupoperations = ko.observable(operators);     self.lines = ko.observablearray([{         operations: ko.observable()     }]);     self.addline = function (line) {         line.lines.push({             operations: ko.observable(operators)         })     };     self.removeline = function (line) {         if (self.lines().length > 1) {             self.lines.remove(line);         }     }; };  var filter = function () {     var self = this;     //self.template = ko.observablearray();         self.groupoperationsgroup = ko.observablearray([new groupoperationstemplate()]);     self.addgroupoperator = function (data) {         self.groupoperationsgroup.splice(self.groupoperationsgroup.indexof(data) + 1, 0, new groupoperationstemplate());     }; };  var vm = new filter(); ko.applybindings(vm); 

so, want is, if change select, want pick select changing in bindinghandler. problem is, bindinghandler called every select. begins @ 0 , 1,2,3 , on. hope understand mean.

lets discuss here.

operators array , , use bind select

self.groupoperations = ko.observable(operators);

instead of

self.groupoperations = ko.observablearray([ { "name": "und", "wert": 0 }, { "name": "und nicht", "wert": 1 }, { "name": "oder", "wert": 2 }, { "name": "oder nicht", "wert": 3 } ]); self.selectedvalue = ko.observable();  self.selectedvalue.subscribe(function( newvalue) {    //do whatever want new value }); 

when binding select

 <!-- ko if: $index() < $root.groupoperationsgroup().length - 1 -->         <tr>             <td>                 <select data-bind="options: groupoperations, optionstext: 'name', value: selectedvalue" style="width: 105px;margin-top:5px !important;margin-bottom:5px !important;margin-left:0px !important;"></select>             </td>         </tr>  <!-- /ko -->