Select with Dependency On Each Other and values preselected in knockout

Question

I have one page with a first request where I recover all the necessary data for my page.

This information is like this one:

"A1": 8, "A2": 61, "A3": 585, "A4": null.........etc

Where every value is the id of a specific select which one is loaded in knockout:

<div class="col-lg-3 col-md-3">
    <label class="obligatory">*</label>
    <label for="id_A1">A1</label>
    <select class="form-control" data-bind="options: $root.A1List, optionsText: 'A1name' , optionsValue: 'idA1', value: $data.A1, optionsCaption: '---------------'"></select>
</div>
<div class="col-lg-3 col-md-3">
    <label class="obligatory">*</label>
    <label for="id_A2">A2</label>
    <select class="form-control" data-bind="options: $root.A2List, optionsText: 'A2name' , optionsValue: 'idA2', value: $data.A2, optionsCaption: '---------------'"></select>
</div>
<div class="col-lg-3 col-md-3">
    <label class="obligatory">*</label>
    <label for="id_A3">A3</label>
    <select class="form-control" data-bind="options: $root.A3List, optionsText: 'A1name' , optionsValue: 'idA3', value: $data.A3, optionsCaption: '---------------'"></select>
</div>
<div class="col-lg-3 col-md-3">
    <label class="obligatory">*</label>
    <label for="id_A4">A4</label>
    <select class="form-control" data-bind="options: $root.A4List, optionsText: 'A4name' , optionsValue: 'idA4', value: $data.A4, optionsCaption: '---------------'"></select>
</div>

These select have Dependency On Each Other in function of the choice you choose:

root.A2List = ko.observableArray([]);
root.A2ListFuncion = ko.computed(function(){
    $.ajax({
        url: RUTA_GLOBAL + "/api/A2/",
        dataType: 'json',
        async: true,
        type:'GET',
        data: {
            A1: root.Data().A1()
        },
        success: function(data) {
            root.A2List(ko.mapping.fromJS(data)());
        }
    });

}, root);
root.A3List = ko.observableArray([]);
root.A3ListFuncion = ko.computed(function(){
    $.ajax({
        url: RUTA_GLOBAL + "/api/A3/",
        dataType: 'json',
        async: true,
        type:'GET',
        data: {
            A1: root.Data().A1()
            A2: root.Data().A2()
        },
        success: function(data) {
            root.A3List(ko.mapping.fromJS(data)());
        }
    });

}, root);
root.A4List = ko.observableArray([]);
root.A4ListFuncion = ko.computed(function(){
    $.ajax({
        url: RUTA_GLOBAL + "/api/A4/",
        dataType: 'json',
        async: true,
        type:'GET',
        data: {
            A1: root.Data().A1()
            A2: root.Data().A2()
            A3: root.Data().A3()
        },
        success: function(data) {
            root.A4List(ko.mapping.fromJS(data)());
        }
    });

}, root);

I got all the values ​​of every select Correctly , but I lose the correct value or id Which one Should be selected the first time the user make the request . I understand due to computed list of my select , feature I want but I need the first time When the pre -selected value in every select the first time the page is loaded.

Any idea?

Answer 1

Thanks Artem by your clue:

root.A3ListFuncion = ko.computed(function(){
    $.ajax({
        url: RUTA_GLOBAL + "/api/A3/",
        dataType: 'json',
        ***async: false,***
        type:'GET',
        data: {
            A1: root.Data().A1()
            A2: root.Data().A2()
        },
        success: function(data) {
            root.A3List(ko.mapping.fromJS(data)());
        }
    });

Changing the ajax request to async false the problme was resolved.